LATHE  DESIGN, 

CONSTRUCTION  AND   OPERATION' 

WITH  PRACTICAL  EXAMPLES  OF 

LATHE   WORK 

A  COMPLETE  PRACTICAL  WORK  ON 

THE  LATHE.  GIVING  ITS  ORIGIN  AND  DEVELOPMENT.  ITS  DE- 
SIGN. ITS  VARIOUS  TYPES  AS  MANUFACTURED  BY  DIFFERENT 
BUILDERS,  INCLUDING  ENGINE  LATHES,  HEAVY  LATHES,  HIGH- 
SPEED LATHES,  SPECIAL  LATHES,  TURRET  LATHES,  ELECTRI- 
CALLY DRIVEN  LATHES,  AND  MANY  OTHERS.  LATHE  ATTACH- 
MENTS, LATHE  WORK,  LATHE  TOOLS,  RAPID  CHANGE  GEAR 
MECHANISMS,  SPEEDS  AND  FEEDS,  POWER  FOR  CUTTING  TOOLS, 
LATHE  TESTING,  TURNING  TAPERS,  METHODS  OF  MILLING  AND 
GRINDING  IN  THE  LATHE,  THREAD  CUTTING,  LATHE 
INSTALLATION,  ETC. 

BY 

OSCAR  E.  PERRIGO,  M.E. 

Author  of  "  Modern  Machine  Shop  Construction,  Equipment  and 
Management,"  "  Change  Gear  Devices,"  etc.,  etc. 


NEW  REVISED  AN  ft  EN^AKGWi  EDITIONS 


Illustrated  by  Three  HAindrett>rld  For  iy-ohe;  Engra^in^s^ 
Made  from  Drawings  fexp>es;3y  Executed  for  this*  feoc-fc-  ' 


NEW  YORK 

THE  NORMAN  W.  HENLEY  PUBLISHING  CO. 

2  WEST  45TH  STREET 

1919 


COPYRIGHT,  1916  AND  1907,  BY 
THE  NORMAN  W.  HENLEY  PUBLISHING  CO. 


Note. — Each  and  every  illustration  in  this  book  was 
specially  made  for  it,  and  is  fully  covered  by  copyright. 


COMPOSITION,     PRINTING     AND      BINDING      BY 
THE  PLIMPTON  PRESS,  NORWOOD,  MASS.,  U.S.A. 


PREFACE 

THE  aim  of  the  Author  in  writing  this  book  has  been  to 
present  in  as  comprehensive  a  manner  as  may  be  within  the 
limits  of  a  single  volume  the  history  and  development  of  the  lathe 
from  early  times  to  the  present  day;  to  briefly  discuss  its  effects 
upon  manufacturing  interests;  to  describe  its  practical  use  on 
various  classes  of  work;  and  to  compare  in  a  representative, 
theoretical,  and  practical  manner  the  Modern  American  Lathes 
as  now  built  in  this  country. 

In  carrying  out  these  aims  the  early  history  of  the  lathe  is 
traced  from  its  crude  beginning  up  to  the  time  when  the  foot- 
power  lathe  was  the  sole  reliance  of  the  early  mechanic.  Then 
the  early  history  of  the  development  of  the  screw-cutting  or 
engine  lathe  is  taken  up  and  carried  on  to  the  middle  of  the  last 
century.  This  is  done  to  put  the  student  and  the  younger 
mechanic  in  possession  of  the  facts  in  relation  to  the  origin  and 
development  of  the  lathe  up  to  within  the  memory  of  many  of 
the  older  mechanics  of  the  present  day. 

The  matter  relating  to  the  early  history  of  the  lathe  is 
introduced  for  what  seem  to  be  good  and  sufficient  reasons.  If 
we  are  always  to  " commence  where  our  predecessors  left  off" 
we  shall  miss  much  valuable  information  that  would  be  very 
useful  to  us.  A  retrospective  glance  on  what  has  been,  a  review 
of  previous  efforts,  a  proper  consideration  of  the  road  by  wnich 
we  came,  or  by  which  earlier  workers  have  advanced,  is  not 
only  interesting  but  necessary  to  a  full  and  complete  under- 
standing of  the  subject,  and  very  useful  to  us  in  mapping  out 
the  course  for  our  continued  advancement  in  contributing  our 
share  in  the  development  of  mechanical  science. 

Following  along  these  lines,  the  various  types  of  lathes  have 

3 


been  carefully  classified,  engravings  and  descriptions  of  the  prom- 
inent American  lathes  are  given,  and  their  special  features  of 
design,  construction,  and  use  are  pointed  out  and  briefly  com- 
mented upon. 

It  is  a  matter  of  much  pride  to  every  true  American  mechanic 
that  this  country  produces  so  many  really  good  and  meritorious 
manufacturing  machines,  and  in  no  line  is  this  superiority  more 
clearly  shown  than  in  the  magnificent  array  of  Modern  Lathes. 

This  work  brings  these  machines  together  in  a  comprehensive 
manner  for  the  first  time,  and  thus  aims  to  add  its  quota  to  the 
present  literature  on  this  subject,  and  so  make  it  valuable  as  a 
book  of  reference,  alike  to  the  student,  the  designer  and  the  me- 
chanic, as  well  as  the  manufacturer  and  the  purchaser  of  Modern 
American  Lathes. 

In  the  revised  and  enlarged  edition  of  this  work  a  chapter  has 
been  added  detailing  all  kinds  of  lathe  work,  treating  of  lathe 
installation  and  management,  milling,  drilling  and  grinding  attach- 
ments and  their  use,  methods  of  turning  tapers,  turning  spherical 
surfaces,  making  oil  grooves  and  many  other  processes  pertaining 
to  practical  lathe  work.  Endeavor  has  been  made  to  have  this 
information  sufficiently  clear  so  it  may  be  readily  followed  by 
the  apprentice,  student  or  amateur  machinist. 

THE  AUTHOR. 

January,  1919. 


CONTENTS 


INTRODUCTION 
CHAPTER  I 

HISTORY  OF  THE  LATHE  UP  TO  THE  INTRODUCTION  OF  SCREW 
THREADS 

PAGE 

Tracing  early  history.  —  The  lathe  was  the  first  machine  tool.  —  The 
origin  of  the  lathe.  —  An  old  definition  of  turning.  —  The  first 
record  of  turning  operations.  —  Another  old-time  definition  of 
turning.  —  English  classification  of  lathes.  —  The  earliest  form 
of  the  lathe  proper,  or  the  old  "Tree  Lathe."  •  —  The  Asiatic  wood 
turner. —  The  "Spring-pole"  lathe. —  The  "Fiddle-bow"  lathe. 

—  The  essential  features  of  a  lathe.  —  The  balance-wheel  applied 
to  a  lathe.  —  The  crank,  connecting  rod  and  treadle,  applied  to  a 
lathe.  —  Origin  of  the  term  "Pitman."-— A  foot  lathe  built  by 
the  Author.  —  A  foot  lathe  with  the  balance-wheel  located  over- 
head. —  The  friction  clutch  for  foot-power  machines  ....       21 

CHAPTER  II 

THE  DEVELOPMENT  OF  THE  LATHE  SINCE  THE  INTRODUCTION 
OF  SCREW  THREADS 

Origin  of  the  screw  thread.  —  Ancient  boring  tools.  —  Suggestions  of 
the  screw  form.  —  The  "Worm  Gimlet."  -—Making  the  first  nuts. 

—  An  old  device  for  cutting  threads  in  wood.  —  Archimedes  and 
his  helical  device  for  raising  water.  —  Jacques  Berson's  French 
lathe.  —  Joseph  Moxan's  English  lathes.  —  The  French  lathe  of 
1772.  —  John  Maudsley's  English  lathes.  —  Maudsley's  slide-rest. 

—  Another  French  lathe.  —  The  use    of   a  "master  screw."  — 
A  form  of  slide-rest.  —  An    old-time    worm    and  worm-gear.  — 
Simple  method  of  developing  the  screw  thread.  —  Anthony  Robin- 
son's triple-threaded  screw.  —  The  many  uses  of  the  early  lathes. 

—  An  old  "chain  lathe."  —  Cutting  left-hand  threads.  —  Crown 
gear  and  "lantern  pinion"  for  operating  the  lead  screw.  —  Tran- 
sition from  wooden  to  iron  lathe  beds.  —  The  Putnam  lathe  of 
1836.  —  The  Freeland  lathe  of  1853.  —  Various  classes  of  lathes 

to  be  illustrated  and  described        .      .      .      .      .     .     ...      .       35 

5 


6  CONTENTS 

CHAPTER  III 

CLASSIFICATION    OF    LATHES 

PAGE 

The  essential  elements  of  a  lathe.  —  The  bed.  —  The  head-stock.  — 
The  tail-stock.  —  The  carriage.  —  The  apron.  —  The  turning  and 
supporting  rests.  —  The  countershaft.  —  Taper  attachments.  — 
Change  gears.  —  Classification  applied  to  materials,  labor  ac- 
counts, and  the  handling  of  parts  in  the  manufacture  of  lathes. 

—  The  four  general  classes  of  lat-hes.  —  The  eighteen  sub-divisions 
of  these  classes.  —  The  first  class :  hand  lathes,  polishing  lathes, 
pattern  lathes,  spinning  lathes,  and  chucking  lathes.  —  The  sec- 
ond class:  engine  lathes  without  thread-cutting  mechanism,  Fox 
brass  lathes,  forge  lathes,  and  roughing  lathes.  —  The  third  class : 
complete  engine  lathes  with  thread-cutting  mechanism,  precision 
lathes,  rapid  reduction  lathes  and  gap  lathes.  —  The  fourth  class: 
forming  lathes,  pulley  lathes,  shafting  lathes,  turret  lathes,  and 
multiple  spindle  lathes.  —  Rapid    change  gear    devices.  —  Ban- 
croft and  Sellers  device.  —  The  Norton  device.  —  Lathe  bed  sup- 
ports. —  The   precision  lathe.  —  The  rapid  production  lathe.  — 
The    gap    lathe.  —  Special    lathes.  —  Forming    lathes.  —  Pulley 
lathes.  —  Shafting  lathes.  —  Turret  lathes.  —  Screw  machines.  — 
Multiple  spindle  lathes.  —  Variety  of  special  lathes   ....       50 

CHAPTER  IV 

LATHE  DESIGN:  THE  BED  AND  ITS  SUPPORTS 

The  designer  of  lathes.  —  The  manufacturer's  view  of  a  lathe.  —  The 
proper  medium.  —  Causes  of  failure.  —  The  visionary  designer. 

—  Conscientious  efforts  to  improve  in  design.  —  Design  of  the  lathe 
bed.  —  Elementary  design.  —  Professor  Sweet's  observations.  — 
The   parabolic   form   of   lathe   beds.  —  The   Author's   design.  — 

/  Form  of  the  tracks.  —  Bed  of  the  old  chain  lathe.  —  The  English 
method  of  stating  lathe  capacity.  —  Method  of  increasing  the 
swing  of  the  lathe.  —  The  Lodge  &  Shipley  lathe  bed.  —  Uniform 
thickness  of  metal  in  beds.  —  Ideal  form  of  bed.  —  Cross-ties, 
or  bars.  —  Four  Vs.  —  Flat  surfaces.  —  Lathe  bed  supports.  — 
Height  of  lathe  centers.  —  Wooden  legs  for  lathe  beds.  —  An 
early  form  of  braced,  cast  iron  legs.  —  Cabinets  or  cupboard 
bases. —  Old  style  cast  iron  leg  still  in  use.  —  Form  of  cabinets. 

—  Principles  of  the  design  of  cabinets.  —  Cabinets  for  small  lathes. 

—  The  Lodge  &  Shipley  cabinet.  —  The  Hendey-Norton  cabinet    .       69 


CONTENTS 


CHAPTER  V 

LATHE  DESIGN:  THE  HEAD-STOCK  CASTING,  THE  SPINDLE  AND 
THE  SPINDLE  CONE 

PAGE 

Design  of  head-stock  for  wooden  bed  lathes.  —  Early  design  for  use 
on  a  cast  iron  bed.  —  An  old  New  Haven  head-stock.  —  The  arch 
form  of  the  bottom  plate.  —  Providing  for  reversing  gears.  —  The 
Hendey-Norton  head-stock.  —  The  Schumacher  &  Boye  head- 
stock.  —  The  Le  Blond  head-stock.  —  The  New  Haven  head- 
stock.  —  The  arch  tie  brace  of  the  new  Hendey-Norton  design.  — 
Generalities  in  describing  a  lathe  spindle.  —  Designing  a  spindle. 

—  Governing  conditions.  —  The  nose  of   the    spindle.  —  Spindle 
collars.  —  Proper  proportions  for  lathe  spindles.  —  Large  versus 
long  bearings.  —  Design  of  the  spindle  cone 93 

CHAPTER  VI 

LATHE  DESIGN:  THE  SPINDLE  BEARINGS,  THE  BACK  GEARS 
AND  THE  TRIPLE  GEAR  MECHANISM 

Designing  spindle  bearings  and  boxes.  —  Thrust  bearings.  —  The 
Lodge  &  Shipley  form.  —  Ball  bearings.  —  Proper  metal  for  boxes. 

—  The  cast  iron  box.  —  Early  form  of  boxes.  —  The  cylindrical 
form.  —  Thrust  bearings  for  a  light  lathe.  —  Experiments  with 
different  metals  on  high  speeds.  —  Curved  journals.  —  The  in- 
volute curve.  —  The  Schiele  curve.  —  Conical  bearings.  —  Adjust- 
ments to  take  up  wear.  —  Split  boxes.  —  Line-reaming  boxes.  — 
Lubrication  of  spindle  bearings.  —  The  plain  brass  oil   cup.  — 
The  use  of  a  wick.  —  Oil  reservoirs.  —  Loose  ring  oilers.  —  Chain 
oilers.  —  Lodge  &  Shipley  oil  rings.  —  Neglect  of  proper  lubrica- 
tion. —  Back    gearing.  —  Varying    the   spindle    speeds.  —  Triple 
gearing.  —  Theory  of  back  gearing.  —  Back  gear  calculations.  — 
Triple  gear  calculations.  —  Diagram  of  spindle  speeds.  —  Faulty 
designing  of  back  gears  and  triple  gears.  —  Four  examples.  —  A 
14-inch  swing  lathe.  —  A  19-inch  swing  lathe.  —  A  17-inch  swing 
lathe.  —  A  30-inch  swing  triple-geared  lathe.  —  Explanation    of 
the    back    gear    diagrams.  —  Essential   parts  of  the  triple  gear 
mechanism.  —  "Guesswork"  in  lathe  designing.  —  Wasted  oppor- 
tunities. —  Designing    the    head-stock.  —  Cone     diameters.  —  A 
homely  proportion.  —  The  modern  tendency  in  cone  design.  — 
Proportions  of  back  gears.  —  Driving  the  feeding  mechanism.  — 
Reversing   the   feed.  —  Variable    feed    devices.  —  Rapid    change 
gear  devices 110 


8  CONTENTS 


CHAPTER  VII 

LATHE  DESIGN:  THE  TAIL-STOCK,  THE  CARRIAGE,  THE 
APRON,  ETC. 

PAGE 

Functions  of  the  tail-stock.  —  Requisites  in  its  construction.  —  The 
Pratt  &  Whitney  tail-stock.  —  The  Reed  tail-stock.  —  The  Lodge 
&  Shipley  tail-stock.  —  The  Blaisdell  tail-stock.  —  The  Hendey- 
Norton  tail-stock.  —  The  New  Haven  tail-stock.  —  The  Prentice 
tail-stock.  —  The  Schumacher  &  Boye  tail-stock.  —  The  Davis 
tail-stock.  —  The  American  Watch  Tool  tail-stock.  —  The  Niles 
tail-stock  for  heavy  lathes.  —  New  Haven  tail-stock  for  heavy 
lathes.  —  The  Schumacher  &  Boye  tail-stock  for  heavy  lathes.  — 
The  Bridgford  tail-stock  for  heavy  lathes.  —  The  Le  Blond  tail- 
stock.  —  The  lever  tail-stock.  —  The  lathe  carriage.  —  Requisites 
for  a  good  design.  —  Description  of  a  proper  form.  —  A  New 
Haven  carriage  for  a  24-inch  lathe.  —  The  Hendey-Norton  car- 
riage. —  The  Blaisdell  carriage.  —  The  New  Haven  carriage  for 
a  60-inch  lathe.  —  Criticisms  of  a  practical  machinist  on  carriage 
and  compound  rest  construction.  —  Turning  tapers.  —  The  taper 
attachment.  —  Failures  of  taper  attachments.  —  The  Reed  taper 
attachment.  —  The  Le  Blond  attachment  taper.  —  The  Lodge  & 
Shipley  taper  attachment.  —  The  Hamilton  taper  attachment.  — 
The  Hendey-Norton  taper  attachment.  —  The  New  Haven  taper 
attachment.  —  The  Bradford  taper  attachment 135 

CHAPTER  VIII 

LATHE  DESIGN:  TURNING  RESTS,  SUPPORTING  RESTS,  SHAFT 
STRAIGHTENERS,  ETC. 

Holding  a  lathe  tool.  —  The  old  slide-rest.  —  The  Reed  compound 
rest.  —  The  Lodge  &  Shipley  compound  rest.  —  The  Hamilton 
compound  rest.  —  The  Hendey-Norton  open  side  tool-posts.  — 
Quick-elevating  tool-rest.  —  The  Homan  patent  tool-rest.  —  The 
Le  Blond  elevating  tool-rest.  —  The  Lipe  elevating  tool-rest.  — 
Revolving  tool  holder.  —  The  full  swing  rest.  —  The  Le  Blond 
three-tool  rest.  —  The  New  Haven  three-tool  shafting  rest.  — 
The  Hendey  cone  pulley  turning  rest.  —  Steady  rests.  —  Follow 
rests.  —  The  usual  center  rest.  —  The  New  Haven  follow  rest.  — 
The  Hendey  follow  rest.  —  The  Reed  follow  rest.  —  The  Lodge  & 
Shipley  follow  rest.  —  Their  friction  roll  follow  rest.  —  Shaft 
straighteners.  —  The  Springfield  shaft  straightener.  —  New  Haven 
shaft  straightener.  —  Lathe  countershafts.  —  The  two-speed  coun- 
tershaft. —  Geared  countershafts.  —  The  Reed  countershaft.  — 
Friction  pulleys.  —  Tight  and  loose  pulleys.  —  Self-oiling  boxes.  — 


CONTENTS  9 

PAGE 

The  Reeves'  variable  speed  countershaft.  —  Design  of  geared  coun- 
tershafts. —  Another  form  of  variable  speed  countershafts     .     .     157 

CHAPTER  IX 

LATHE   ATTACHMENTS 

Special  forms  of  turned  work.  —  Attachment  for  machining  concave 
and  convex  surfaces.  —  Attachment  for  forming  semicircular 
grooves  in  rolling  mill  rolls.  —  Device  for  turning  balls  or  spherical 
work.  —  Turning  curved  rolls.  —  A  German  device  for  machining 
concave  surfaces.  —  A  ^similar  device  for  convex  surfaces.  —  Mak- 
ing milling  cutters.  —  Backing-off  or  relieving  attachment.  — 
Cross-feed  stop  for  lathes.  —  Grinding  attachments.  —  The  "home- 
made "  attachment.  —  Electrically  driven  grinding  attachment.  — 
Center  grinding  attachment.  —  Large  grinding  attachment.  —  The 
Rivett-Dock  thread-cutting  attachment  .  .  .  .  .  .  .  .  176 

CHAPTER  X 

RAPID  CHANGE  GEAR  MECHANISMS 

What  a  rapid  change  gear  device  is.  —  The  old  pin  wheel  and  lantern 
pinion  device.  —  The  first  patent  for  a  rapid  change  gear  device. 

—  The  inventors'  claims.  —  Classification  of  rapid  change  gear 
devices.  —  The  inventors  of  rapid  change  gear  devices.  —  Paulson's 
originality.  —  " Change  gear  devices"  by  the  Author.  —  Le  Blond's 
quick  change  gear  device.  —  The  Springfield  rapid  change  gear 
attachment. — The  Bradford  rapid  change  gear  device.  —  Judd's 
quick  change  gear  device.  —  Newton's  quick  change  gear  device. 

—  Flather  quick  change  gear  device 194 

CHAPTER  XI 

LATHE  TOOLS,  HIGH-SPEED  STEEL,   SPEEDS    AND  FEEDS,  POWER 
FOR  CUTTING-TOOLS,    ETC. 

Lathe  tools  in  general.  —  A  set  of   regular  tools.  —  Tool  angles.  — 
Materials  and  their  characteristics.  —  Their  relation  to  the  proper 
form  of  tools.  —  Behavior  of    metals  when  being    machined.  — 
The  four  requisites  for  a  tool.  —  The  strength  of  the  tool.  —  The 
form  of  the  tool.  —  Degree  of  angles.  —  Roughing  and  finishing 
tools.  —  Spring  tools.  —  Tool-holders.  —  Grinding  /  tools    for  tool 
holders.  —  Dimensions  of  tools  for  tool-holders.  —  The  Armstrong 
tool-holders.  —  Economy  of  the  use  of  tool-holders.  —  High  speed 
steel.  —  A  practical  machinist's  views  on  high-speed  steel  tools.  — 
Conditions  of  its  use.  —  Preparing  the  tool.  —  Testing  the  tool.  — 


10  CONTENTS 

PAGE 

—  Speeds  and  feeds.  —  Much  difference  of  opinion.  —  Grinding 
the  tools.  —  Amount  of  work  accomplished  by  high-speed  steel 
tools.  —  Average  speed  for  lathes  of  different  swing.  —  Speeds  of 
high-speed  steel   drills.  —  Mr.   Walter   Brown's  observations  on 
high-speed  steel.  —  Its  brittleness.  —  Its  treatment.  —  The  secret 
of  its  successful  treatment.  —  Method  of  hardening  and  tempering. 
Method  of  packing.  —  Making  successful  taps.  —  Speeds  for  the  use 
of  high-speed  steel  tools.  —  Economy  in  the  use  of  high-speed  steel 
tools.  —  Old  speeds  for  carbon  steel  tools.  —  Modern  speeds.  — 
Relative  speeds  and  feeds.  —  Modern  feeds  for  different  materials. 

—  Lubrication  of  tools.  —  The  kind  of  lubricant.  —  Applying  the 
lubricant.  —  Lubricating  oils.  —  Soapy  mixtures.  —  Formula  for 
lubricating  compound.  —  Improper  lubricants.  —  Various  methods 
of  applying  lubricants.  —  The  gravity  feed.  —  Tank  for  lubricant. 

—  Pump  for  lubricant.  —  Power  for  driving  machine  tools.  — 
Calculating  the  power  of  a  driving  belt.  —  Impracticability  of 
constructing  power  tables.  —  Collecting  data  relating  to  these  sub- 
jects. —  Flather's    "  Dynamometers    and    the    Transmission    of 
Power."  —  Pressure  on  the  tool.  —  Method  of  calculating  it. — 
Flather's  formula.  —  Manchester  Technology  data.  —  Pressure  on 
tools 214 

CHAPTER  XII 

TESTING   A   LATHE 

Prime  requisites  of  a  good  lathe.  —  Importance  of  correct  tests.  —  The 
Author's  plan.  —  Devices  for  testing  alignment.  —  Using  the  de- 
vice. —  Adjustable  straight-edge.  —  Development  of  the  plan.  — 
Special  tools  necessary.  —  Proper  fitting-up  operations.  —  Level- 
ing up  the  lathe  for  testing.  —  An  inspector's  blank.  —  The  in- 
spector's duties.  —  Testing  lead  screws.  —  A  device  for  the  work. 

—  A  micrometer  surface  gage.  —  Its  use  in  lathe  testing.  —  Proper 
paper  for  use  in  testing.  —  Test  piece  for  use  on  the  face-plate.  — 
Testing  the  face-plate.  —  A  micrometer  straight-edge.  —  Allow- 
able limits  in  testing  different  sized  lathes.  —  Inspection  report  on 

a  lathe.  —  Value  of  a  complete  and  accurate  report       ....     240 

CHAPTER  XIII 

LATHE   WORK 

The  use  of  hand  tools.  —  Simple  lathe  work.  —  Lathe  centers.  —  Care 
in  reaming  center  holes.  —  Locating  the  center.  —  Use  of  the 
center  square.  —  Angle  of  centers.  —  Lubrication  of  centers.  — 
Centering  large  pieces  of  work.  —  Driving  the  work.  —  Lathe  dogs. 


CONTENTS  11 

PAGE 

—  The  clamp  dog.  —  The  die  dog.  —  The  two-tailed  dog.  —  Lathe 
drivers. — Using  dogs  on  finished  work.  —  Clamp  dog  for  taper  work. 

-  Bolt  dog.  —  Methods  of  holding  work  that  cannot  be  centered. 

—  Center  rest  work.  —  Chuck  work.  —  Use  of  face-plate  jaws.  — 
Lathe  chucks.  —  The  Horton  chuck.  —  The  Sweetland  chuck.  — 
The  Universal  chuck.  —  Face-plate  jaws.  —  A    Horton  four-jaw 
chuck.  —  A  Horton  two-jaw  chuck.  —  A  Cushman  two-jaw  chuck. 

—  Chucking    cylindrical    work.  —  Inside    chucking.  —  Chucking 
work   supported   in    a   center   rest.  —  Pipe    centers.  —  Mortimer 
Parker's  improved  forms  of  pipe  centers.  —  Spider  centers.  —  Ball- 
thrust   pipe    centers.  —  Lathe    arbors   or   mandrels.  —  Kinds   of 
mandrels.  —  Expanding    arbors    or    mandrels.  —  Making    solid 
arbors.  —  The  taper  of  an  arbor.  —  Hardened  and  ground  arbors. 

—  The  Greenard  arbor  press.  —  Its  advantages 254 

CHAPTER  XIV 

LATHE   WORK   CONTINUED 

Irregular  lathe  work.  —  Clamping  work  to  the  face-plate.  —  Danger 
of  distorting  the  work.  —  A  notable  instance  of  improper  holding 
of  face-plate  work.  —  The  turning  of  tapers.  —  Setting  over  the 
tail-stock  center.  —  Calculating  the  amount  of  taper.  —  Taper 
attachments.  —  Graduations  on  taper  attachments.  —  Disadvan- 
tages of  taper  attachments.  —  Fitting  tapers  to  taper  holes.  — 
Taper  turning  lathes.  —  Turning  crank  shafts.  —  Counterbalan- 
cing the  work.  —  Angle  plate  for  holding  the  crank  shaft.  —  Form- 
ing work.  —  Forming  lathes.  —  Drilling  work  on  the  lathe.  — 
Chuck  and  face-plate  drilling.  —  Holding  work  on  the  carriage.  — 
Boring  a  cylinder.  —  The  Author's  design  for  boring  large  cylin- 
ders. —  Holding  work  by  an  angle-plate  on  the  face-plate.  — 
Thread  cutting.  —  Calculations  for  change-gears.  —  Reverse  gears. 

—  Arrangement  of    the    change-gears.  —  Ratio    of    change-gears 
equal  to  ratio  of  lead  screw  to  the  thread  to  be  cut. — Cutting  left- 
hand    threads.  —  Compound    gearing.  —  Calculating    compound 
gears.  —  Cutting  double  threads.  —  Triple  and  quadruple  threads. 

—  Boring  bars.  —  Varieties  of  boring  bars.  —  Driving  boring  bars. 

—  Boring  large  and  deep  holes.  —  The  Author's  device.  —  The 
drill  boring  bar  and  cutters  for  the  work.  —  Flat  cutters  for  boring 
bars.  —  Boring  bar  heads  or  arms.  —  Hollow  boring  bars.  —  Mill- 
ing work  on  a  lathe.  —  Milling  and  gear  cutting  on  a  speed  lathe.  — 
Grinding  in  a  lathe.  —  Cam  cutting  on  a  lathe.  —  Many  uses  for 

the  engine  lathe 268 


12  CONTENTS 

CHAPTER  XV 

ENGINE   LATHES  PAGE 

Definition  of  the  word  engine. — What  is  meant  by  an  engine  lathe.  — 
The  plan  of  this  chapter.  —  The  Reed  lathes.  —  Reed  18-inch 
engine  lathe.  —  The  Pratt  &  Whitney  lathes.  —  Their  14-inch 
engine  lathe.  —  Flather  lathes.  —  Flather  18-inch  quick  change 
gear  lathe. — Prentice  Brother's  Company  and  their  16-inch  engine 
lathe.  —  The  Blaisdell  18-inch  engine  lathe.  —  The  New  Haven 
21-inch  engine  lathe.  —  Two  lathe  patents  by  the  Author.  —  The 
Hendey-Norton  lathes.  —  Who  were  the  pioneers  in  quick  change 
gear  devices?  —  The  Hendey-Norton  24-inch  engine  lathe.  —  The 
Lodge  &  Shipley  20-inch  engine  lathe 286 

CHAPTER  XVI 

ENGINE   LATHES   CONTINUED 

Schumacher  &  Boye's  20-inch  instantaneous  change-gear  engine  lathe. 

—  Emmes  change-gear  device.  —  32-inch    swing    engine    lathe.  — 
Le  Blond  engine  lathes.  —  24-inch  swing  lathe.  —  The  Le  Blond 
lathe   apron.  —  Complete   drawing   of   a   front   elevation.  —  The 
Bradford  Machine  Tool  Company's  16-inch  swing  engine  lathe.  — 
The  American  Tool  Works  Company's  20-inch  engine  lathe.  — 
The  Springfield  Machine  Tool  Company's  16-inch  engine  lathe. 

—  The  Hamilton  Machine  Tool  Company's  18-inch  engine  lathe. 

—  The  W.  P.  Davis  Machine  Company's  18-inch  engine  lathe.  — 

The  Fosdick  Machine  Tool  Company's  16-inch  engine  lathe      .     .     307 

CHAPTER  XVII 

'    HEAVY   LATHES 

The  Bradford  Tool  Company's  42-inch  triple-geared  engine  lathes.  — 
The  American  Tool  Works  Company's  42-inch  triple-geared  engine 
lathe.  —  The  New  Haven  Manufacturing  Company's  50-inch  triple- 
geared  engine  lathe.  —  The  Niles  Tool  Works  72-inch  triple-geared 
engine  lathe.  —  The  Pond  Machine  Tool  Company's  84-inch  engine 
lathe 327 

CHAPTER  XVIII 

HIGH-SPEED   LATHES 

Prentice  Brothers  Company's  new  high  speed,  geared  head  lathe.  —  A 
detailed  description  of  its  special  features.  —  R.  K.  Le  Blond 
roughing  lathe.  —  Lodge  &  Shipley's  patent  head  lathe.  —  The 
prime  requisites  of  a  good  lathe  head.  —  Description  of  the  lathe 
in  detail.  —  The  capacity  of  the  lathe.  —  A  24-inch  special  turning 
lathe  built  by  the  F.  E.  Reed  Company.  —  A  two-part  head-stock. 

—  The  special  rest.  —  Its  two  methods  of  operation.  —  Its  special 
countershaft.  —  The  Lo-swing  lathe,  built  by  the  Fitchburg  Ma- 


CONTENTS  13 

PAGE 

chine  Tool  Works.  —  Its  peculiar  design.  —  A  single  purpose  ma- 
chine. —  An  ideal  machine  for  small  work.  —  Builders  who  have 
the  courage  of  their  conviction 338 

CHAPTER  XIX 

SPECIAL   LATHES 

The  F.  E.  Reed  turret  head  chucking  lathe.  —  Its  special  features.  — 
A  useful  turning  rest.  —  The  Springfield  Machine  Tool  Company's 
shaft  turning  lathe.  —  The  three-tool  shafting  rest.  —  The  driv- 
ing mechanism.  —  Lubrication  of  the  work.  —  The  principal  dimen- 
sions. —  Fay  &  Scott's  extension  gap  lathe.  —  Details  of  its 
design.  McCabe's  double-spindle  lathe.  —  Its  general  features.  — 
Its  various  sizes.  —  Pulley-turning  lathe  built  by  the  New  Haven 
Manufacturing  Company.  —  A  special  crowning  device.  —  Its 
general  design.  —  A  defect  in  design.  —  The  omission  of  a  valu- 
able feature.  —  Pulley-turning  lathe  built  by  the  Niles  Tool  Works. 
—  A  pulley-turning  machine.  —  Its  general  construction.  —  Turn- 
ing angular  work.  —  Convenience  of  a  bench  lathe.  —  The  Waltham 
Machine  Company's  bench  lathe.  —  A  grinding  and  a  milling 
machine  attachment.  —  Devising  a  special  attachment.  —  Reed's 
10-inch  wood-turning  lathe.  —  Special  features  of  design.  — 
Popularity  and  endurance.  —  The  countershaft.  —  Inverted  V's  .  .  353 

CHAPTER  XX 

REGULAR   TURRET   LATHES 

Importance  of  the  turret  lathe.  —  Its  sphere  of  usefulness.  —  Classi- 
fication of  turret  lathes.  —  Special  turret  lathes.  —  The  monitor 
lathes.  —  The  Jones  &  Lamson  flat  turret  lathe.  —  Its  general 
design  and  construction.  —  Its  special  features.  —  Its  tool.  — 
The  Warner  &  Swasey  24-inch  universal  turret  lathe.  —  General 
description.  —  Its  capacity.  —  Taper  turning  attachment.  —  Its 
speeds.  —  The  Bullard  Machine  Tool  Company's  26-inch  com- 
plete turret  lathe.  —  Its  massive  form  and  its  general  design  and 
construction. —  Lubrication  of  tools. —  The  countershaft. —  The 
Pratt  &  Whitney  3  by  36  turret  lathe.  —  Its  special  features.  — 
Its  general  design.  —  Its  capacity.  —  Special  chuck  construction 
and  operation.  —  The  Gisholt  turret  lathe.  —  Its  massive  design 
and  construction.  —  Its  large  capacity.  —  Its  general  and  special 
features.  —  The  .Pond  rigid  turret  lathe.  —  Its  heavy  and  sym- 
metrical design.  —  Detailed  description.  —  Its  operation.  —  Gen- 
eral dimensions .»  . 370 

CHAPTER  XXI 

SPECIAL  TURRET  LATHES 

The  R.  K.  Le  Blond  triple-geared  turret  lathe.  —  The  Springfield  Ma- 
chine Tool  Company's  24-inch  engine  lathe  with  a  turret  on  the 


14  CONTENTS 

PAGE 

bed.  —  Turret  lathe  for  brass  work  built  by  the  Dreses  Machine 
Tool  Company.  —  Special  features  and  construction.  —  A  combi- 
nation turret  lathe  built  by  the  R.  K.  Le  Blond  Machine  Tool 
Company.  —  A  useful  machine  with  many  good  features.  —  A 
15-inch  swing  brass  forming  lathe  built  by  the  Dreses  Machine 
Tool  Company.  —  Le  Blond  Machine  Tool  Company's  plain  turret 
lathe.  —  Plainness  and  simplicity  its  strongest  points.  —  The 
Springfield  Machine  Tool  Company's  hand  turret  lathe.  —  A 
modification  of  their  18-inch  swing  engine  lathe.  —  The  Pratt  & 
Whitney  monitor  lathe  or  turret  head  chucking  lathe  ....  391 

CHAPTER  XXII 

ELECTRICALLY   DRIVEN   LATHES 

System  of  electric  drives.  —  Principal  advantages  of  driving  lathes  by 
electricity.  —  Group  drive  versus  individual  motor  system.  — 
Individual  motor  drives  preferable  for  medium  and  large  sized 
lathes.  —  The  Reed  16-inch  motor-driven  lathe.  —  The  Lodge  & 
Shipley  24-inch  motor-driven  lathe.  —  The  Prentice  Brothers 
Company's  motor-driven  lathes.  —  General  description.  —  Crocker- 
Wheeler  motors.  —  Renold  silent  chain.  —  The  Hendey-Norton 
lathe  with  elevated  electric  motor  drive.  —  Special  features.  —  A 
50-inch  swing  lathe  with  electric  motor  drive  designed  by  the 
Author.  —  Detailed  description.  —  Practical  usefulness.  —  Not 
strikingly  original,  but  successful 405 

CHAPTER  XXIII 

PRACTICAL  INSTRUCTIONS   ON   LATHE    OPERATION 

Setting  up  a  lathe.  —  Placing  the  lathe.  —  Plan  of  small  shop.  —  Line 
shaft  size  and  speed.  —  Power  needed  to  drive  lathes.  —  Leveling 
lathe.  —  Lubrication  of  lathe  parts.  —  When  to  oil.  —  Attaching 
face  plate  or  chuck.  —  Lathe  parts  and  their  functions.  —  Head- 
stock. — Tail-stock. — Carriage.— Automatic  apron. — Reverse  gear. — 
Compound  Rest. — Starting  the  lathe.  —  Operating  levers.  —  Simple 
lathe  accessories. —  Spur  and  screw  centers. —  Drill  pads. —  Turning 
a  steel  shaft.  —  Drilling  in  the  lathe.  —  Taper  attachment  for 
lathes.  —  Milling  in  the  lathe.  —  South  Bend  attachment.  —  Barnes 
attachment.— Motor  driven  attachment.— Knurling  on  the  lathe.— 
Indicators  and  their  use.  —  Boring  bar  construction  and  use.  — 
Adjustable  boring  bars.  —  Boring  bars  for  heavy  work.  —  Methods 
of  holding  work.  —  Special  chuck  for  gas  engine  pistons.  —  In- 
creasing swing  of  lathe.  —  Lathes  for  heavy  work.  —  Grinding  at- 
tachments. —  Machining  concave  and  convex  surfaces.  —  Grooving 
oil  ducts.  —  Combination  lathe  dogs  and  their  use.  —  Hacksaw 
attachment  for  lathes 417 

INDEX  461 


INTRODUCTION 

IN  the  great  measure  of  success  that  has  been  enjoyed,  and  the 
vast  volume  of  wealth  that  has  been  produced  in  this,  the  most 
industrial  of  all  countries,  the  manufacturing  industries  easily  lead 
all  other  productive  interests  in  which  the  people  are  engaged. 
While  in  the  earlier  years  of  American  independence  the  chief 
dependence  was  upon  the  results  of  agriculture,  the  development 
of  the  resources  of  the  country  in  time  has  placed  manufactures 
at  the  head  of  the  list  so  that  in  very  recent  years  the  value 
of  manufactures  has  been  nearly  double  the  amounts  of  that 
produced  by  agricultural  pursuits. 

These  results,  like  many  others  of  a  less  notable  character, 
commenced  from  small  beginnings,  and  it  has  been  by  inborn 
mechanical  talent,  remarkable  ingenuity,  patient  development, 
and  tireless  energy,  that  mechanical  undertakings  large  and  srriall 
have  been  developed,  until  the  American  mechanic  leads  the  world 
in  originality  and  practical  achievement  in  our  vast  manufactur- 
ing enterprises. 

When  the  early  settlers,  the  Puritans  of  New  England,  labored 
under  the  restrictive  and  harassing  laws  of  the  mother-country, 
and  under  their  administration  were  goaded  and  exasperated 
beyond  endurance  in  many  ways,  not  the  least  of  which  was  being 
obliged  to  purhase  all  their  manufactured  articles  from  England 
at  extortionate  prices,  or  from  other  countries  and  still  paying 
taxes  to  England,  they  rebelled  and  determining  to  buy  no  more 
foreign  goods,  set  out,  at  first  in  very  primitive  and  clumsy  ways, 
to  make  such  articles  as  were  really  necessary,  and  in  magnificent 
self-denial  to  get  along  without  those  which  they  could  not  pro- 
duce, they  little  realized  that  they  were  thus  laying  the  founda- 
tions of  the  greatest  manufacturing  country  in  the  world. 

By  their  action  they  thus  instituted  probably  the  first  industrial 
"boycott"  in  the  history  of  the  country,  and  one  that  has  had 

15 


16 


'INTRODUCTION 


more  important  anU  far-reaching  influences  than  any  since  its 
day. 

It  is  true  that  the  coming  of  the  Pilgrims,  their  departure 
from  the  old  country,  was  for  religious  freedom,  but  freedom  soon 
meant  vastly  more  to  them  than  this,  and  with  this  larger  concep- 
tion of  their  opportunities,  some  of  which  were  really  forced  upon 
them  by  adverse  circumstances,  came  the  inspiration  of  industrial 
as  well  as  religious  freedom.  And  the  determined  manner  in 
which  they  set  about  their  self-appointed  task  has  amply  demon- 
strated  to  their  posterity  and  to  the  world  their  grasp  of  the  pos- 
sibilities and  conditions  of  the  situation  as  well  as  their  breadth 
and  nobility  of  character. 

Thus  sprang  American  manufactures  into  being,  beginning 
with  crude  efforts  to  fashion  those  common  objects  of  household 
necessity  and  daily  use,  which,  clumsy  though  they  were,  yet 
served  their  practical  purposes,  to  be  supplanted  later  on  by  those 
more  improved  in  form,  design,  and  workmanship  and  better 
adapted  to  the  uses  for  which  they  were  made.  The  primitive 
successes  of  these  early  efforts  led  to  greater  endeavors,  and  the 
ingenuity  displayed  where  "  necessity  was  the  mother  of  inven- 
tion" was  naturally  developed  into  a  still  broader  usefulness  when 
the  time  came  that  necessities  having  been  reasonably  provided 
for,  luxuries  were  thought  necessary  in  the  higher  plane  of  living 
to  which  the  people  in  due  course  had  advanced. 

And  so  it  came  about  that  the  rude  and  crude  beginnings  in 
which  the  early  mechanic  performed  his  work  in  his  own  house 
outgrew  these  homely  facilities  and  he  built  small  shops,  frequently 
in  the  gardens  or  back  yards  of  the  dwellings.  These  gradually 
enlarged;  then  came  the  necessity  for  still  greater  facilities,  and 
buildings  were  erected  quite  independent  of  the  home  surround- 
ings and  two  or  more  men  were  associated  as  manufacturers,  and 
these  became  in  due  course  of  time  the  machine  shops  and  the 
factories,  which  have  multiplied  many  hundreds  of  times,  not  only 
in  numbers  and  in  value,  but  in  influence  and  in  importance,  until 
to-day  our  country  stands  the  leading  manufacturing  nation  of 
the  earth.  And  this  may  be  said,  not  only  as  to  the  volume  and 
the  value  of  her  manufactured  productions,  but  also  as  to  their 
great  range  and  diversity  of  kind  and  degree.  One  after  another 


INTRODUCTION  17 

the  American  mechanic  has  taken  up  the  work  formerly  monopo- 
lized by  this  country  or  that,  failing  perhaps  at  first,  but  always 
progressing,  always  advancing,  until  by  native  ingenuity  and  tire- 
less energy  all  obstacles  have  been  surmounted,  all  difficulties 
brushed  aside,  new  industries  spring  into  being  and  other  "vic- 
tories of  peace  greater  than  the  glories  of  war"  are  added  to  the 
credit  of  the  American  mechanic  and  his  ever  ready  and  ever  con- 
fident partner,  the  American  manufacturer  and  capitalist.  And 
to  this  combination,  each  confident  of  and  faithful  to  the  abilities 
of  the  other,  and  each  in  his  own  sphere  of  usefulness,  is  due  the 
immense  success  of  the  manufacturing  American  of  to-day. 

In  the  early  stages  of  manufacturing  in  this  country  all  the 
tools  and  appliances  were  of  a  very  crude  and  primitive  kind  and 
consisted  mainly  of  a  limited  number  of  hand  tools  that  had  been 
brought  with  them  from  the  old  country,  and  occasionally  a  hand 
lathe  of  moderate  dimensions,  operated  by  foot-power.  Yet  with 
even  these  few  facilities  much  important  work  was  accomplished 
in  the  way  of  useful  machines  such  as  the  flax  and  woolen  spinning 
wheels  and  their  accessories,  and  the  wooden  looms  in  which  the 
yarn  thus  prepared  was  woven  into  the  coarse  but  excellent  cloth 
of  these  early  times. 

Then  with  the  few  tools  and  meager  facilities  possessed  by  them 
these  old-time  mechanics  proceeded  with  practical  common  sense, 
ingenuity,  and  patience  to  design  and  construct  other  tools  and 
machines  such  as  by  the  necessities  of  occasion  was  manifest,  and  the 
increasing  demands  for  them  required  better  tools,  better  machin- 
ery, and  facilities  of  a  wider  scope.  The  mechanic  was  then,  as 
now,  equal  to  the  emergencies  of  the  situation  in  which  he  found 
himself,  and  from  small  beginnings,  and  many  of  the  parts  of  his 
machines  made  of  wood,  for  lack  of  forge  and  foundry  facilities, 
particularly  the  latter,  has  developed  the  machine  tools  of  the 
present  day. 

The  lack  of  facilities  for  making  iron  castings  was  very  early 
felt,  and  history  tells  us  that  as  early  as  the  year  1643  John  Winthrop 
arrived  in  this  country  from  England,  bringing  with  him  the  neces- 
sary number  of  skilled  workmen  for  this  purpose,  and  built  a  small 
iron  foundry  in  Lynn,  Mass.;  and  the  fact  that  the  first  casting 


18  INTRODUCTION 

produced  was  "a  small  iron  pot  holding  about  a  quart "  shows 
that  the  foundry  was  of  very  moderate  capacity,  and  it  is  very 
likely  that  the  blast  used  in  melting  the  iron  was  produced  by  a 
hand  bellows,  as  the  blacksmith  forge  had  preceded  the  foundry 
here,  as  it  did,  probably,  in  all  other  countries.  The  quart  pot  was 
cast  from  iron  "made  from  native  ore,"  although  we  do  not  know 
where  they  obtained  it;  probably  from  some  place  in  the  vicinity 
where  it  was  found  in  small  quantities.  From  this  small  begin- 
ning there  was  very  little  progress  made  for  a  considerable  time 
in  enlarging  either  the  original  scope  of  the  work  or  in  increasing 
its  facilities,  so  far  as  we  have  any  record.  In  1735,  nearly  one 
hundred  years  later,  we  know  that  an  iron  foundry  was  built  in  the 
little  town  of  Carver,  Mass.,  and  that  a  second  one  was  put  up  in 
the  same  town  in  1760,  although  we  do  not  know  the  reason  for 
this  second  one  coming  into  existence  in  the  same  town  unless  it 
was  that  the  first  one  had  been  destroyed  by  fire.  However,  it 
was  in  this  second  foundry  that  the  historic  "  Massachusetts  Tea- 
kettle" was  cast.  We  do  know  that  still  another  foundry  was 
built  in  this  town  in  1793  and  that  this  was  burned  down  in  1841. 
Thus  early  did  the  custom  begin,  which  is  still  in  vogue  in  eastern 
Massachusetts,  of  devoting  the  energy  of  a  town  to  one  line  of 
manufacture. 

While  these  events  and  evidences  of  mechanical  progress  were 
taking  place,  the  active  minds  of  ingenious  workmen  were  busily 
engaged  in  solving  the  practical  problems  of  the  growing  demands 
made  upon  the  shops  and  embryo  manufactories  engaged  in  supply- 
ing the  wants  of  the  people.  New  methods  of  manufacture,  by 
which  the  quality  as  well  as  the  quantity  turned  out  could  be  im- 
proved, were  demanded.  This  led  to  the  demand  for  more  machin- 
ery, which  in  turn  led  to  the  demand  for  better  machines  for  the 
use  of  the  mechanic,  or  for  what  we  have  come  to  know  as  machine 
tools.  In  the  meantime  the  main  reliance  had  been  upon  the  an- 
cient foot  lathe,  and  with  it  much  of  their  mechanical  work  had 
been  accomplished.  It  had  been  improved  in  various  ways,  both 
in  its  design  and  in  the  materials  of  which  it  was  constructed,  and 
with  the  use  of  water-power  for  driving  the  machinery  for  manu- 
facturing operations  the  lathe  had  become  of  greater  usefulness 
by  being  driven  in  the  same  manner.  Yet  from  the  first  it  main- 


INTRODUCTION  19 

tained  its  prominence  as  the  first  of  the  machine  tools  and  the  one 
which  made  all  of  the  others  that  came  after  it  possible  of  con- 
struction and  useful  in  their  several  and  respective  spheres. 

In  the  great  scheme  of  manufacturing  and  the  immense  indus- 
trial problem  of  supplying  the  wants  of  the  people  in  this  respect 
by  modern  manufacturing  plants  equipped  with  all  that  is  latest 
and  best  in  machinery,  it  should  be  said  that  at  the  very  basis  and 
foundation  of  the  whole  stand  the  modern  machine  tools;  that 
it  is  to  the  great  and  important  development  of  these  that  we  owe, 
primarily,  our  industrial  prosperity  as  a  nation.  And  to  them 
may  be  easily  traced  the  gradual  upward  tendency  of  the  mechanic 
from  the  hard  physical  toil  and  laborious  work  of  early  days  to 
the  immeasurably  lighter  exertions  made  possible  by  the  highly 
developed  condition  of  the  automatic  machines  of  the  present  day. 
It  has  been,  as  was  said  in  the  outset,  a  victory  of  mind  over  matter, 
wherein  brains  have  won  where  the  hands  made  little  advance; 
ideas  developed  wonderful  mechanisms  that  have  revolutionized 
the  earlier  methods  of  manufacturing,  raised  the  standard  of 
mechanical  excellence  beyond  what  was  thought  possible  years 
ago,  and  at  the  same  time  reduced  the  cost  to  a  fraction  of  its 
former  amount.  But  to  attain  these  marvelous  results  many 
machines  have  been  required.  All  conceivable  types  and  styles, 
and  for  an  almost  endless  variety  of  purposes,  have  been  de- 
signed, built,  and  perfected  until  hardly  a  possible  mechanical 
operation  is  performed  without  the  aid  of  a  machine,  frequently 
special  in  its  design  and  automatic  in  its  action,  is  brought  into 
use,  performing  the  work  with  surprising  speed  and  wonderful 
accuracy. 

The  construction  and  perfection  of  all  this  magnificent  array 
of  highly  developed  machinery  has  only  been  made  possible  through 
the  use  of  the  machines  for  the  use  of  the  machinist,  the  machine 
tools  of  the  present  day,  which  must  first  have  been  perfected  and 
adapted  to  the  many  needs  and  requirements  which  the  advanced 
state  of  mechanical  science  demanded.  These  machine  tools  were 
made  possible  by  the  earlier  examples  of  the  most  simple  devices 
in  this  direction,  chiefly,  in  our  own  time,  the  foot  lathe,  by  which 
many  of  the  earlier  tools  and  machines  were  for  the  most  part 
built;  and  as  new  uses  for  it  were  found  new  devices,  attach- 


20  INTRODUCTION 

ments,  and  accessories  were  devised  and  applied,  and  in  this 
gradual  development  and  improvement  in  its  design,  its  con- 
struction, and  the  materials  of  which  it  is  built,  the  early  and 
crude  foot  lathe  has  become  the  magnificent  machine  of  the 
present  day,  and  in  which  the  American  mechanic  takes  a  just 
and  pardonable  pride. 

As  to  how  this  development  progressed  will  be  discussed  in  the 
opening  chapters,  and  it  is  hoped  that  it  will  be  found  interesting 
to  every  American  mechanic  and  particularly  to  the  apprentice 
who  is  about  to  start  out  with  learning  the  honorable  trade  of  a 
machinist,  and  the  student  who  would  know  from  whence  our 
modern  machine  tools  were  derived,  that  he  may  perhaps,  in  due 
time,  become  one  of  those  who  shall  aid  in  their  further  develop- 
ment and  perfection,  as  well  as  to  the  elder  mechanic  who  uses 
these  machines,  and  the  mechanical  engineer  who  is  busy  with  their 
present  development.  It  is  always  profitable  to  take  a  retrospec- 
tive glance  at  the  former  state  and  condition  of  the  matter  upon 
which  we  are  engaged,  in  order  that  we  may  not  only  realize  from 
whence  came  the  models  built  by  the  men  who  came  before  us, 
and  to  draw  therefrom  an  inspiration  for  our  own  best  efforts,  but 
knowing  the  mistakes  that  have  been  made  by  others,  to  seek  to 
avoid  repeating  them  in  our  own  experiences,  our  experiments  and 
our  designs  by  which  we  seek  to  add  to  the  sum  total  of  mechanical 
knowledge  and  improvement. 


CHAPTER  I 

HISTORY  OF  THE  LATHE  UP  TO  THE  INTRODUCTION  OF  SCREW  THREADS 

Tracing  early  history.  The  lathe  was  the  first  machine  tool.  The  origin 
of  the  lathe.  An  old  definition  of  turning.  The  first  record  of  turn- 
ing operations.  Another  old-time  definition  of  turning.  English 
classification  of  lathes.  The  earliest  form  of  the  lathe  proper,  or  the 
old  "Tree  Lathe."  The  Asiatic  wood  turner.  The  "Springpole" 
lathe.  The  "Fiddle-bow"  lathe.  The  essential  features  of  a  lathe. 
The  balance-wheel  applied  to  a  lathe.  The  crank,  connecting  rod  and 
treadle  applied  to  a  lathe.  Origin  of  the  term  "Pitman."  Afoot 
lathe  built  by  the  Author.  Its  detailed  construction.  A  foot  lathe 
with  the  balance-wheel  located  over-head.  The  friction  clutch  for 
foot-power  machines. 

THE  subject  of  the  present  work  being  the  lathe  and  its  work, 
and  more  particularly  its  design,  construction,  and  develop- 
ment in  our  own  country  and  in  recent  years,  and  as  briefly  com- 
prised in  our  title  of  Modern  American  Lathe  Practice,  our 
efforts  will  be  directed,  first,  to  a  brief  notice  of  its  origin  and  early 
development  and  use  as  a  simple  hand  lathe;  second,  to  its  more 
modern  development  as  one  of  the  most  important  machine  tools 
in  the  equipment  of  machine  shops;  and,  third,  to  the  various 
modifications  of  it,  following  its  development  through  all  its  vari- 
ous forms  and  for  the  diversity  of  manufacturing  purposes  to  which 
it  has  been  adapted  up  to  its  present  degree  of  efficiency. 

In  considering  a  subject  of  the  vast  importance  of  the  modern 
lathe  and  its  far-reaching  influence  upon  the  mechanical  world 
of  to-day,  it  cannot  but  be  interesting  to  go  back  to  its  early  his- 
tory and  to  trace  its  progress  and  development  from  as  far  back 
as  we  have  any  authentic  knowledge,  and  step  by  step  to  note  the 
changes  in  its  form  and  usefulness  as  the  mind  of  the  early  mechanic 
developed,  new  requirements  manifested  themselves,  and  improve- 
ments in  design,  construction,  tools,  and  attachments  were  devised 
to  meet  the  growing  needs. 

21 


22  MODERN  LATHE  PRACTICE 

It  is  conceded  that  of  all  the  machines  employed  by  the  me- 
chanic to  aid  him  in  his  work  the  lathe  holds  the  honor  of  having 
been  the  first  machine  tool,  From  it,  in  one  way  or  another,  all 
other  machine  tools  have  been  developed;  as  they  are,  practically 
considered,  but  modifications  of  it,  or  special  tools  for  doing  quicker 
and  better,  the  several  operations  which  may  be,  and  formerly  were, 
performed  upon  the  lathe,  as  we  shall  later  on  have  occasion  to 
describe  and  illustrate. 

At  present  we  will  look  into  the  origin  of  the  lathe  and  then 
trace  its  gradual  evolution  and  development  up  to  comparatively 
recent  years,  say  an  hundred  years  or  so  ago,  as  their  development 
into  anything  like  mechanical  importance  has  been  confined  to 
the  last  century  which  has  been  so  remarkable  in  this  respect. 

Upon  referring  to  the  older  records  on  the  subject  of  lathes 
and  their  uses  we  find  this  statement:  " Turning  is  the  art  of 
shaping  wood,  metal,  ivory,  or  other  hard  substances  into  forms 
having  a  curved  (generally  circular  or  oval)  transverse  section, 
and  also  of  engraving  figures  composed  of  curved  lines  upon  a 
smooth  surface,  by  means  of  a  machine  called  a  turning-lathe. 
This  art  is  of  great  importance  and  extensive  application  in  me- 
chanics, the  most  delicate  articles  of  luxury  and  ornament,  equally 
with  the  most  ponderous  machinery,  being  produced  by  it.  The 
art  of  turning  dates  from  a  very  early  period,  and  Theodorus  of 
Samos,  about  560  B.C.,  is  named  by  Pliny  as  its  inventor;  but  long 
before  this  period,  the  potter's  wheel,  the  earliest  and  simplest  form 
of  turning-machine,  was  in  general  use,  as  is  evidenced  by  numer- 
ous references  in  Holy  Writ." 

Again  we  read  in  an  old-time  definition  of  what  turning  really 
consists  of:  "The  immense  variety  of  work  performed  by  turning- 
machines  necessitates  great  variations  in  their  construction;  but 
mode  of  operation  is  always  the  same,  and  consists  essentially  in 
fixing  the  work  in  position  by  two  pivots,  or  otherwise,  causing 
it  to  revolve  freely  around  an  axis  of  revolution,  of  which  the 
two  pivots  are  the  poles,  and  holding  a  chisel  or  other  cutting-tool 
so  as  to  meet  it  during  its  revolution,  taking  care  that  the  cutting- 
tool  be  held  firmly  and  steadily,  and  moved  about  to  different  parts 
of  the  work  till  the  required  shape  is  obtained." 

In  England  the  various  methods  of  driving  a  lathe   gives  a 


HISTORY  OF  THE  LATHE 


23 


classification  to  them  somewhat  different  from  that  in  this  country. 
Hence  the  following:  " Lathes  are  divided,  with  respect  to  the 
mode  of  setting  them  in  motion,  into  pole  lathes,  foot  lathes,  hand- 
wheel  lathes,  and  power  lathes;  and  with  respect  to  the  species  of 
work  they  have  to  perform,  into  center  lathes,  which  form  the 
outside  surface,  and  spindle,  mandrel,  or  chuck  lathes,  which  per- 
form hollow  or  inside  work,  though  this  distinction  is  for  the  most 
part  useless,  as  all  lathes  of  good  construction  are  now  fitted  for 
both  kinds  of  work."  Another  peculiarly  English  idea  in  refer- 
ence to  lathes  is  this:  "Bed  lathes  are  those  used  by  turners  in 
wood,  and  bar  lathes  for  the  best  sort  of  metal  work;  and  the  small 
metal  center  lathe  employed  by  watchmakers  is  known  as  a  turn- 
bench." 

The  earliest  form  of  a  lathe  proper,  that  is,  "a  machine  for 
shaping  wood  into  forms  having  a  curved,  and  generally  a  circular 
transverse  section,  by  the 
action  of  a  chisel  or  other 
cutting  tool  upon  the  piece, 
which  is  rotated  for  the  pur- 
pose," is  shown  in  the  en- 
graving Fig.  1,  and  consists, 
as  will  be  seen,  of  two  pointed 
pieces  A,  A  of  wood  serving 
as  centers  and  each  bound  to 
a  tree,  and  supporting  the 
ends  of  the  piece  C  to  be 
turned,  while  on  the  opposite 
side  of  the  tree  is  fixed  in 
the  same  manner  a  straight 
piece  of  wood  B,  which  acts 
as  a  rest  for  the  chisel  or 
other  tool  with  which  the 
turning  or  cutting  is  to  be  done.  The  power  for  rotating  the 
piece  C  to  be  turned  is  obtained  by  attaching  a  cord  D  to  a  flexi- 
ble limb  of  the  tree,  passing  it  one  or  more  turns  around  the  piece 
and  forming  in  its  lower  end  a  loop  for  the  foot  of  the  operator,, 
who  rotates  the  piece  towards  himself  by  depressing  the  foot, 
bending  down  the  limb  by  the.  movement,  which,  when  he.  raises 


FIG.  1.  —  The  Old  Tree  Lathe 


24  MODERN  LATHE  PRACTICE 

his  foot,  returns  to  its  original  position,  rotating  the  piece  back- 
wards in  readiness  for  another  pressure  or  downward  stroke  of 
the  foot.  The  work  was  slow  and  laborious,  yet  from  old  samples 
of  the  pieces  thus  produced  we  may  see  that  an  extraordinary 
good  quality  of  work  could  be  done,  particularly  considering  the 
primitive  methods  used. 

We  read  that: 

"  Wood-turners  in  some  of  the  Asiatic  countries  go  into  the 
deep  forests  with  axes,  and  with  a  few  rude  turning  tools  and 
hair  ropes  build  their  lathes  and  turn  out  objects  of  beauty  and 
grace,  says  the  Wood  Worker.  Two  trees  are  selected  which  stand 
the  proper  distance  apart  near  a  springy  sapling.  With  his  ax 
the  turner  cuts  out  his  centers  and  drives  them  opposite  each 
other  into  the  trees,  which  serve  as  standards.  From  one  tree 
to  the  other  he  places  a  stick  of  wood  for  a  tool-rest.  With  his 
ax  he  trims  the  branches  from  the  sapling,  fastens  his  hair  rope 
to  the  little  tree,  gives  the  rope  a  turn  around  one  end  of  the 
block  of  wood  he  desires  to  turn  into  shape,  and  fastens  the  free 
end  of  the  rope  to  a  stick  which  he  uses  as  a  foot  treadle.  When 
he  presses  down  on  the  treadle  the  wood  he  is  turning  revolves, 
and  the  spring  of  the  sapling  lifts  the  treadle  so  that  it  can  be 
used  again." 

The  next  form  of  lathe  to  which  these  crude  efforts  seem  to 
have  led  was  one  in  which  the  flexible  limb,  though  in  another 
form,  was  used,  but  the  device  became  very  nearly  a  self-contained 
machine.  A  piece  of  wood  formed  a  bed  for  the  lathe  and  to  this 
was  fixed  the  blocks  forming  the  centers,  which  have  since  become 
the  head  and  tail  stocks  of  the  lathe.  The  machine  appears  to 
have  been  used  in  doors,  as  the  flexible  limb  of  the  tree  had  been 
replaced  by  a  flexible  strip  or  pole,  "  fastened  overhead"  and  called 
a  "lath"  from  which  circumstance  some  writers  think  that  the 
name  "lathe"  was  derived.  The  driving  cord  was  still  wound 
around  the  piece  to  be  turned.  No  mention  is  made  of  the  method 
of  supporting  the  tool,  but  it  is  probable  that  a  strip  of  wood  was 
fastened  to  the  "bed"  for  that  purpose. 

The  next  improvement  in  developing  the  lathe  brings  its  form 
within  the  memory  of  the  older  mechanics  and  is  shown  in  Fig.  2. 
In  this  case  there  is  a  rude  form  of  head-stock  B,  and  tail-stock  E; 


HISTORY  OF  THE  LATHE 


25 


both  constructed  at  first  of  wood,  and  the  tail-stock  continuing 
to  be  so  constructed  for  many  years.  In  this  form  of  lathe  the 
head  spindle  is  first  found,  having  in  the  earlier  examples  a  plain 
" spool"  around  which  the  driving  cord  D  was  wound,  and  later 
on  a  cone  pulley  constructed  as  shown  in  Fig.  3,  by  which  a  faster 
speed  was  possible  with  the  same  movement  of  the  foot.  The 
lower  end  of  the  driving  cord  was  fastened  to  a  strip  of  wood  F, 
the  farther  end  of  which  was  pivoted  to  the  rear  leg,  in  the  later 
examples  of  the  "  spring-pole  lathe,"  as  it  was  then  called,  the 
bed  having  been  mounted  upon  legs  as  shown. 

The  bed  A,  was  formed  of  two  pieces  of  timber  set  on  edge  and 


FIG.  2.  —  The  "  Spring-Pole  "  Lathe. 

a  short  distance  apart,  properly  secured  at  the  ends.  This  afforded 
a  space  down  through  which  passed  a  long  tennon  formed  upon  a 
wooden  block  answering  for  a  tail-stock  E.  This  was  held  in  any 
desired  position  by  a  wooden  key,  passing  through  it  under  the  bed. 

What  was  the  early  form  of  rests  for  this  lathe  does  not  seem  to 
be  known,  but  somewhat  later  the  rest  was  constructed  of  cast  iron 
and  very  much  as  in  an  ordinary  hand  lathe  of  the  pattern-maker 
or  wood-turner  of  the  present  day,  and  as  shown  in  Fig.  2. 

This  lathe  was  used  for  both  wood  and  metal,  the  tools  being 
held  in  the  hand  as  the  slide  rest  had  not  yet  been  invented,  as 
will  be  seen  later  on  in  this  chapter. 

In  the  use  of  the  spring  pole  and  cord  in  connection  with  the 


26 


MODERN   LATHE  PRACTICE 


cone  pulley,  as  shown  in  Fig.  3,  some  workman  discovered,  prob- 
ably by  turning  a  heavy  piece,  that  its  forward  motion  would  con- 
tinue when  the  foot  was  raised,  provided  the  tool  was  withdrawn 
from  contact  with  the  work.  It  was  but  natural  to  make  the  cone 
pulley  of  heavier  material,  as  of  cast  iron,  or  to  weight  it  with 
pieces  of  iron  or  with  lead  plugs  cast  into  it,  and  thus  make  it  serve 
the  office  of  a  balance-wheel  and  so  keep  up  the  forward  revolution 
of  the  work  as  long  as  it  was  given  the  proper  impetus  by  the  down- 
ward strokes  of  the  foot. 

Another  style  of  lathe  that  was  used  mostly  for  small  work, 
generally  metal  work,  was  called  a  "  fiddle-bow  lathe,"  on  account 
of  the  method  of  driving  it.  In  this  lathe,  which  is  shown  in  Fig.  4, 


FIG.  4.  — The  " Fiddle-Bow"  Lathe. 

the  same  idea  of  propulsion  is  used  as  in  the  former  examples,  that 
of  a  cord  passing  around  either  the  piece  to  be  turned  or  a  rotating 
part  of  the  mechanism  by  which  the  piece  was  revolved.  In  this 
case,  however,  instead  of  the  resistance  of  the  flexible  limb  of  a 
tree  or  of  a  " spring  pole"  acting  to  keep  the  driving  cord  taut, 
it  is  held  in  that  condition  by  the  flexible  bow  F,  which  is  bent  to 
the  form  shown  by  the  driving  cord  D.  The  engraving  is  an  exact 
reproduction  of  a  lathe,  the  bed  A  of  which  was  about  twelve 


HISTORY   OF  THE  LATHE  27 

inches  long  and  it  had  a  capacity  of  about  two  inches  swing,  that 
was  made  by  an  older  brother  for  the  use  of  the  author  when  he 
was  nine  years  old,  and  in  the  use  of  which  he  became  quite  a 
boyish  expert  in  turning  wood  and  metals.  The  head-stock  B, 
and  rest  C,  were  formed  of  bent  pieces  of  wrought  iron,  and  the 
"spur  center"  was  formed  upon  the  main  spindle,  the  point  being 
used  as  a  center  for  metal  work. 

Lathes  driven  in  this  manner  are  still  in  use  by  watchmakers 
and  jewelers  and  a  great  deal  of  very  fine  hand  work  is  performed 
with  them. 

The  main  features  in  all  these  lathes  were,  first,  to  suspend 
the  work  to  be  done,  or  the  piece  to  be  operated  upon,  between 
two  fixed  pivots  or  centers;  second,  to  revolve  it  by  means  of  a 
cord  wrapped  around  it,  or  some  part  of  the  machine  fixed  to  it, 
and  kept  tightly  strained  by  means  of  some  kind  of  a  spring,  as 
an  elastic  piece  of  wood;  and  third,  to  reduce  the  piece  to  be  oper- 
ated upon  by  means  of  a  tool  having  a  cutting  edge  which  was 
held  tightly  against  the  material  to  be  operated  upon,  thus  reduc- 
ing it  to  the  circular  form  required;  fourth,  that  to  accomplish 
this  it  was  necessary  to  revolve  the  piece  to  be  operated  upon, 
first  towards  the  cutting  tool  for  a  certain  number  of  revolutions, 
then  by  a  reverse  motion  of  the  taut  cord  to  reverse  the  circular 
motion,  at  the  same  time  withdrawing  the  cutting-tool  for  an 
equal  number  of  revolutions.  By  this  method  one  half  the  time 
was  lost,  as  no  cutting  could  be  done  while  the  work  was  running 
backward. 

It  was  later  found  that  if  the  flexible  pole  or  "lath"  was  rather 
weak  and  the  piece  of  work  to  be  operated  upon  was  quite  heavy, 
acting  as  a  balance-wheel,  its  forward  revolution  was  not  wholly 
arrested,  but  only  checked  as  the  foot  was  raised,  provided  the 
cutting-tool  was  withdrawn  from  contact  with  the  work  a  moment 
before  the  upward  motion  of  the  foot  began. 

By  this  it  was  seen  that  great  advantages  might  be  gained  if 
the  lathe  could  be  made  to  not  only  revolve  continuously  in  the 
direction  of  the  tool,  but  also  with  the  same  force,  whereby  the 
tool  might  be  kept  in  constant  contact  with  the  work. 

Already  the  pulley,  as  applied  to  the  spindle  of  the  lathe,  was 
known.  The  cord  wrapped  around  it  and  used  to  rotate  it  was 


28  MODERN  LATHE  PRACTICE 

known.  Doubtless  an  assistant  had  furnished  the  power  to  drive 
the  lathe  while  the  mechanic  handled  the  tools.  What  would  be 
more  natural  than  the  arrangement  of  a  large  wheel,  journaled  to 
a  suitable  support  at  the  front  or  rear  of  the  lathe,  and  having  the 
cord  connected  with  it  as  a  driver.  And  with  this  device  and  the 
problem  of  revolving  it  by  hand,  a  handle  set  between  its  center 
and  circumference  would  be  natural  also,  and  thus  came  the  crank. 
We  do  know  that  somewhat  later  than  this  machines  were  driven 
in  exactly  this  manner,  the  large  wheel  being  constructed  with 
a  heavy  rim  and  acting  as  a  balance-wheel. 

At  this  stage  of  development  the  large  driving-wheel  was  rather 
an  attachment  than  a  part  of  the  machine  itself,  and  doubtless  so 
remained  for  a  considerable  time.  The  next  change  was  to  locate 
it  beneath  the  lathe  bed,  directly  under  the  head-stock,  and  in- 
stead of  the  use  of  the  handle  forming  practically  a  crank  of  long 
leverage  it  was  constructed  as  it  is  in  the  sewing-machines  of  the 
present  day;  that  is,  the  wheel  journaled  upon  a  fixed  stud  and 
the  previous  long  handle  reduced  to  a  wrist-pin  for  the  attach- 
ment of  a  connecting  rod,  or  in  the  older  phrase  a  "  pitman,"  which 
term  was  given  to  one  of  the  men  handling  the  vertical  saw  used 
in  sawing  up  logs  into  timber  and  planks  in  the  olden  times  (and 
even  now  in  oriental  countries),  wherein  the  log  was  supported 
over  a  trench  or  pit,  the  upper  end  of  the  saw  being  handled  by 
the  "topman"  and  the  lower  end  by  the  " pitman"  or  man  in  the 
pit.  When  these  saws  were  later  on  mounted  in  a  rectangular 
frame  or  "gate"  having  a  vertical,  reciprocating  movement  and 
operated  from  a  crank-shaft  by  a  connecting  rod  from  the  one  to 
the  other,  this  rod  took  the  name  of  the  former  man  who  performed 
this  office,  hence  the  term  "pitman." 

The  location  of  this  pitman  or  connecting  rod,  as  has  been  said, 
was  directly  under  the  head-stock  and  well  within  the  convenient 
reach  of  the  operator  when  attached  to  a  suitable  "treadle"  whose 
rear  end  was  pivoted  to  the  back  of  the  machine  and  whose  front  end 
formed  a  resting-place  for  the  operator's  foot.  This  arrangement 
answered  very  well  and  was  useful  when  the  work  of  the  lathe  was 
near  the  head-stock,  but  was  not  adapted  to  long  work,  to  accomplish 
which  the  operator  would  need  to  stand  near  the  tail-stock  or  even 
midway  between  that  and  the  head-stock.  To  remedy  this  defect 


HISTORY  OF  THE  LATHE  29 

a  strip  of  wood  was  hinged  to  the  front  leg  of  the  lathe  at  the  tail- 
stock  end  and  its  opposite  end  to  the  front  end  of  the  treadle.  This 
was  of  considerable  use,  its  principal  drawback  being  that  while 
at  the  treadle  end  its  vertical  movement  was  the  same  as  the  latter, 
this  movement  was  gradually  lessened  until  at  the  tail-stock  end 
of  the  lathe  it  was  nothing.  Hence,  much  more  power  was  required 
to  drive  the  lathe  at  its  center  than  at  the  head-stock,  and  this  was 
rapidly  increased  as  the  work  was  nearer  the  tail-stock  end  of  the 
lathe. 

To  remedy  this  defect  the  large  driving-wheel  was  mounted 
upon  and  fixed  to  a  revolving  shaft  upon  which  was  formed  two 
cranks,  one  near  the  wheel  and  the  other  at  the  tail-stock  end  of 
the  lathe.  This  shaft  was  properly  journaled  in  boxes  formed 
upon  or  attached  to  cross-bars  fixed  to  the  legs  at  each  end  of  the 
lathe.  From  these  cranks  hung  two  connecting  rods  whose  lower 
ends  were  pivoted  to  two  levers  pivoted  to  the  rear  side  of  the 
lathe,  and  whose  front  ends  were  connected  by  a  wooden  strip  or 
" foot-board."  The  length  of  these  levers  was  such  that  the  move- 
ment of  the  foot-board  was  about  twice  the  "  throw"  of  the  cranks, 
so  that  with  a  foot  movement  of  twelve  inches  the  two  cranks 
were  about  three  inches,  center  of  shaft  to  center  of  connecting 
rod  bearing. 

This  was  then  and  for  many  years  the  prevailing  form  of  foot 
lathes  and  was  quite  extensively  used,  not  only  for  turning  wood 
but  for  iron,  steel,  and  other  metals  as  well. 

There  were  many  of  the  older  mechanics  who  would  work  the 
entire  day  through.  At  that  time  a  day's  work  was  not  eight,  nine, 
or  ten  hours,  but  "from  sun  to  sun,"  or  from  daylight  till  sunset, 
day  after  day,  treading  one  of  these  foot  lathes  and  turning  out 
a  much  larger  quantity  of  work  than  these  crude  facilities  would 
seem  to  render  possible. 

In  Fig.  5  is  shown  this  form  of  foot  lathe  that  was  in  use  for 
many  years  for  turning  both  wood  and  metals.  The  illustration 
is  a  drawing  of  a  lathe  built  by  the  author  when  he  was  between 
fifteen  and  sixteen  years  of  age.  The  bed  A,  legs  B,  the  cross-bars 
C,  C,  the  back  brace  D,  and  treadle  parts  E,  F,  were  built  of  wood, 
as  was  also  the  tail-block  G,  which  was  of  the  form  shown  in  Fig.  4, 
except  that  beneath  the  screw  forming  the  tail  center  was  a  wooden 


30 


MODERN   LATHE  PRACTICE 


key  g,  for  keeping  this  screw  always  tight,  as  there  was  a  tendency, 
from  strain  and  vibration,  for  the  screw  to  work  loose. 

The  tool-rest  was  of  the  usual  form,  except  that  instead  of  a 
wedge,  in  connection  with  the  binder  H,  to  hold  it  in  position,  or 
the  use  of  a  wrench  on  the  holding-down  bolt,  an  eccentric  of  hard 
wood  with  a  handle  formed  upon  it,  as  shown  at  J,  was  used.  This 
was  the  first  occasion  where  the  author  saw  an  eccentric  used  for 
a  similar  purpose.  It  worked  so  well  that  he  fitted  similar  eccentrics 
to  the  stops  of  the  three  windows  in  his  little  workshop  to  hold 
the  sashes  in  any  desired  position  when  they  were  raised,  and  by 


FIG.  5.  —  Foot  Lathe  for  Turning  Wood  or  Metals. 

a  turn  in  the  opposite  direction  to  secure  them  when  they  were 
closed. 

The  large  wheel  was  of  cast  iron,  rescued  from  a  scrap  heap, 
and  had  only  the  grooves  for  the  two  faster  speeds  K,  L,  the  part 
M  being  made  of  wood  and  fastened  to  the  arms  of  the  wheel.  A 
friendly  blacksmith  forged  the  cranks  in  the  shaft  N,  and  the  eyes 
in  the  lower  ends  and  hooks  in  the  upper  ends  of  the  connecting 
rods  P,  P.  These  were  first  made  of  wood  similar  to  the  connect- 
ing rods  on  a  sewing-machine  with  a  closed  bearing  at  the  top,  but 
the  tendency  to  pinch  one's  toes  under  the  treadle  when  they 
happened  to  be  accidentally  placed  in  this  dangerous  position  soon 


HISTORY  OF  THE  LATHE  31 

led  to  the  iron  connecting  rods  with  the  hooked  ends  whereby  the 
worst  that  could  happen  was  the  connecting  rods  becoming  un- 
hooked. The  shaft  N  rested  in  wooden  boxes,  the  lower  half  being 
formed  in  the  cross-bars  C,  C,  and  a  wooden  cap  held  down  by  two 
wood  screws  forming  the  top  half.  The  bearings  of  the  shaft  and 
the  cranks  were  filed  as  nearly  round  as  they  could  be  made  by 
hand  with  the  means  and  ability  available. 

The  pattern  for  the  head-stock  was  made  as  shown  in  side  ele- 
vation in  Fig.  5,  with  the  housings  for  the  spindle  boxes  as  shown 
in  Fig.  6.    The  boxes  were  made  in  halves,  of  babbitt  metal  and 
cast  in  place  in  the  head-stock  in  this  manner. 
The  head  spindle  was  located  in  place  and  held 
by  a  thin  piece  of  wood  clamped  on  the  inside 
and  outside  of  the  housing  and  having  semicir- 
cular notches  in  their  upper  edges  and  a  slight 
recess  on  their  inner  sides  so  as  to  provide  for 

making  the  box  slightly  thicker  than  the  hous- 

inv  FIG.  6.  —  Spindle- 

The  lower  halves  of  the  boxes,  having  been 
cast  slightly  higher  than  the  center  of  the  spindle  bearings,  were 
removed  and  filed  down  to  the  proper  level  and  then  replaced,  the 
spindle  again  laid  in,  the  strips  of  wood  clamped  on  in  an  inverted 
position  and  the  top  half  of  the  box  cast.  This  part  projected 
slightly  above  the  top  of  the  iron  casting  and  was  held  down  by 
an  iron  cap  having  two  holes  drilled  in  it  which  fitted  on  the 
threaded  studs  R,  R,  which  had  been  cast  into  the  head-stock 
for  this  purpose.  The  spindle  had  been  turned  up  in  an  old-style 
chain-feed  lathe,  of  which  more  will  be  said  later  on.  The  cone 
pulley  S  was  of  cherry,  simply  driven  on  tightly  and  turned  up  to 
the  form  shown. 

The  front  end  of  the  spindles  was  threaded  but  not  bored  out. 
Upon  this  thread  was  cast  a  babbitt  metal  bushing  T,  having  a 
square  hole  in  its  front  end,  which  was  formed  as  follows:  With 
the  spindle  in  its  place  a  wooden  mold  of  proper  form  was  placed 
around  it  and,  while  it  fitted  the  collar  on  the  spindle  at  one  end, 
was  open  at  its  front  end.  A  tapering,  square  piece  of  iron  of 
proper  dimensions  to  form  the  square  hole  was  placed  with  its 
small  end  against  the  nose  of  the  spindle  and  held  in  that  position 


32  MODERN  LATHE  PRACTICE 

by  the  tail  screw.  The  opening  around  it  was  closed  by  a  piece 
of  wood  of  proper  form  and  the  job  was  "  poured,"  and  the  bushing 
afterwards  turned  up  with  a  hand  tool.  Into  this  square  hole 
could  be  fitted  proper  centers  for  turning  wood  or  metal,  and  by 
removing  the  babbitt  metal  collar  a  face-plate  could  be  put  on  for 
face-plate  work. 

It  will  be  noticed  that  the  lathe  had  been  arranged  for  two 
speeds  proper  for  turning  wood  and  the  softer  metals,  and  one  speed 
considerably  slower  for  iron.  A  piece  of  belting  was  provided 
which  could  be  easily  removed  to  shorten  the  belt  the  proper 
amount  for  this  purpose. 

The  lathe  would  swing  eight  inches  and  take  in  between  centers 
four  feet.  It  was  found  that  the  round  belt  did  not  give  sufficient 
driving  power  and  a  new  spindle  cone  of  only  two  steps  was  put 
on,  the  iron  balance-wheel  lagged  up  for  a  flat  belt,  and  the  pulley 
M  turned  down  for  the  same  purpose.  This  permitted  the  use 
of  a  belt  an  inch  and  three-quarters  wide,  and  as  no  regular  belting 
was  available  when  the  job  was  done  an  old  trace  from  a  harness 
suffering  from  general  debility  was  ripped  open  and  a  single  thick- 
ness of  the  leather  soaked  up  in  water,  dried  out,  treated  with 
neat's-foot  oil  and  used  with  such  good  results  that  it  was  never 
replaced. 

To  this  lathe  was  fitted  a  small  circular  saw  provided  with  an 
adjustable,  tilting  table  upon  which  not  only  wood  but  sheet  brass 
could  be  cut.  Another  attachment  was  a  small  jig-saw  that  would 
cut  off  wood  up  to  half  an  inch  thick. 

One  of  the  disadvantages  of  the  usual  form  of  foot-power 
lathe  was  the  short  connecting  rod  or  pitman  which  thereby  formed 
too  great  an  angle  to  the  center  line  from  the  wheel  center  to  the 
point  of  attachment  to  the  treadle,  thereby  increasing  the  friction 
and  decreasing  the  useful  effect  of  the  foot-power.  It  was  appar- 
ently to  avoid  this  condition  that  a  somewhat  peculiar  form  of 
lathe  was  devised  and  built  in  the  railroad  shops  at  Plattsburgh, 
N.  Y.,  about  1860,  and  which  is  shown  in  end  elevation  in  Fig.  7. 
This  was  an  engine  lathe  of  about  fourteen-inch  swing,  built  with 
cast  iron  bed  A,  legs  B,  and  all  the  parts  of  metal  that  are  now  so 
constructed.  Instead  of  placing  the  large  driving  or  balance  wheel 
beneath  the  lathe  bed  as  formerly,  the  lathe  was  belted  from  a 


HISTORY   OF  THE  LATHE 


33 


cone  pulley  of  three  steps^on  an  overhead  countershaft  C,  provided 
with  the  usual  hangers  D.  This  countershaft  was  of  a  length  equal 
to  the  length  of  the  lathe  and  had  fixed  at  the  end  over  the  head 
of  the  lathe  a  heavy  wheel  E,  into  the  hub  of  which  was  fixed  a 
stud  or  wrist-pin  F,  while  on  the  opposite  end  of  the  countershaft 
was  fixed  a  disc  for  carrying  a  similar  stud.  These  formed  two 
cranks  to  which  were  fitted  long  connecting  rods  G,  the  lower  ends 
of  which  were  pivoted  to  the  treadles  H,  whose  rear  ends  were 
pivoted  to  the  legs  B,  as  at  J.  The  treadles 
H  are  located  outside  of  the  legs  B,  and 
connected  by  the  foot-board  K.  The 
weight  of  the  connecting  rods  G,  the  tread- 
les H,  and  the  foot-board  K  are  balanced 
by  the  proper  counterbalance  added  to  the 
fly-wheel  E,  as  shown.  The  author  knows 
from  personal  observation  that  this  lathe 
would  run  very  steadily  and  with  a  good 
deal  of  power,  and  that  its  general  perform- 
ance was  much  better  than  foot  lathes  of 
the  usual  type.  Doubtless  the  momentum 
of  the  balance-wheel,  cone  pulley,  and 
countershaft  was  very  beneficial  in  main- 
taining an  equable  speed  under  varying 
conditions  of  resistance  from  the  operation 
of  cutting-tools  and  the  like,  while  the  cast 
iron  cone  pulley  on  the  main  spindle  did 
some  service  in  the  same  direction. 

The  only  disadvantage  in  this  lathe  was 
that  it  required  too  long  a  time  to  get  it 
up  to  its  regular  speed  and  necessarily  too 
much  time  was  consumed  in  stopping  it,  as 
there  was  no  provision  for  disconnecting  the 

main  spindle  from  the  driving-cone  by  a  clutch  mechanism  or 
similar  device,  as  is  frequently  the  case  with  special  forms  of  the 
lathes  of  recent  design. 

There  has  been  manufactured  for  some  years  a  special 
type  of  friction  clutch  that  is  very  useful  in  driving  foot-power 
machinery.  It  consists  essentially  of  a  drum  mounted  upon  and 


FIG.  7.  —  Foot    Lathe, 
Driven  from  a  Coun- 
tershaft. 


34  MODERN  LATHE  PRACTICE 

loosely  revolving  around  the  shaft  to  be  driven,  and  having  a  friction, 
clutch  mechanism  contained  within  it  and  so  operating  that  the 
drum  will  turn  freely  in  one  direction  but  the  moment  it  is  revolved 
in  the  opposite  direction  the  friction  device  comes  into  operation, 
the  drum  is  firmly  clamped  to  the  shaft,  which  is  thus  caused  to 
rotate  with  it.  To  this  drum  is  attached  one  end  of  a  flat  leather 
belt,  which  is  wrapped  around  it  several  times  and  its  free  end 
attached  to  the  movable  end  of  a  treadle,  which  is  usually  hinged 
at  the  front  instead  of  the  back  of  the  machine.  In  operation  the 
pressure  of  the  foot  acting  on  the  drum  by  means  of  the  belt 
rotates  it  in  the  forward  direction,  which  causes  its  friction  mechan- 
ism to  act  and  revolve  the  shaft  through  as  many  revolutions  as 
there  are  convolutions  of  the  flat  belt  around  the  drum.  The 
rotary  motion  thus  set  up  is  continued  by  the  momentum  of  a 
balance-wheel,  and  as  the  foot  is  raised  the  treadle  is  caused  to 
follow  it,  either  by  the  action  of  a  spring  similar  to  a  clock  spring 
within  the  revolving  drum,  or  a  spiral  spring  acting  upon  another 
strap,  also  wrapped  around  the  drum,  but  in  the  opposite  direction 
to  the  one  attached  to  the  treadle.  By  this  device  several  revolu- 
tions of  the  driving-shaft  could  be  produced  at  each  depression 
of  the  foot,  the  treadle  frequently  passing  through  an  arc  of  thirty 
to  forty  degrees. 

This  device  was  particularly  applicable  to  the  driving  of  light 
foot-power  machinery  which  it  did  very  successfully,  and  as  the 
strokes  of  the  foot  need  not  be  of  the  same  length  and  were  not 
confined  to  any  certain  cadence  it  was  not  nearly  as  fatiguing  as 
the  crank  device  in  which  the  strokes  of  the  foot  were  always  the 
same  distance  and  with  the  same  speed. 

In  the  above  described  device,  however,  the  balance-wheel  was 
more  necessary  and  it  was  also  necessary  that  it  should  be  so 
arranged  as  to  revolve  with  a  much  higher  rate  of  speed  than  the 
large  wheel  of  the  older  form  of  foot  lathe.  There  was  one  advan- 
tage in  this  condition,  however,  that  in  consequence  of  its  higher 
speed  the  balance-wheel  could  be  made  of  much  smaller  diameter 
and  consequently  much  lighter  in  weight,  and  therefore  occupying 
much  less  space  under  the  machine. 


CHAPTER  II 

THE    DEVELOPMENT    OF    THE    LATHE    SINCE    THE    INTRODUCTION    OF 

SCREW    THREADS 

Origin  of  the  screw  thread.  Ancient  boring  tools.  Suggestions  of  the  screw 
form.  The  "Worm  Gimlet."  Making  the  first  nuts.  An  old  device 
for  cutting  threads  in  wood.  Archimedes  and  his  helical  device  for 
raising  water.  Jacques  Berson's  French  lathe.  Joseph  Moxan's  Eng- 
lish lathes.  The  French  lathe  of  1772.  John  Maudsley's  English  lathes. 
Maudsley's  slide-rest.  Another  French  lathe.  The  use  of  a  "master 
screw."  A  form  of  slide-rest.  An  old-time  worm  and  worm-gear. 
Simple  method  of  developing  the  screw  thread.  Anthon  Robinson's 
triple-threaded  screw.  The  many  uses  of  the  early  lathes.  An  old 
"chain  lathe."  Its  detailed  construction.  Cutting  left-hand  threads. 
Crown  gear  and  "lantern  pinion  "  for  operating  the  lead  screw.  Transi- 
tion from  wooden  to  iron  lathe  beds.  The  Putman  lathe  of  1836.  The 
Freeland  lathe  of  1853.  Various  classes  of  lathes  to  be  illustrated  and 
described. 

THE  origin  of  the  screw  thread,  or  the  threaded  screw,  reaches 
so  far  back  into  ancient  times  that  it  is  impossible  to  determine 
when,  where,  or  by  whom  it  was  first  conceived  or  used.  That  it 
was  known  in  one  form  or  another  as  far  back  as  the  use  of  iron 
for  tools  is  altogether  probable.  Holes  must  have  been  made  in 
wood  by  some  kind  of  an  iron  instrument  which  was  the  predecessor 
of  the  gimlet.  This  instrument  was  most  likely  square  or  of  some 
form  nearly  approaching  that.  In  order  to  be  at  all  effective  it 
must  have  had  sharp  corners. 

As  the  straight-edged  sharp  knife  was  first  accidentally  and 
then  purposely  hacked  into  notches  and  became  the  first  saw,  so 
may  the  corners  of  the  early  boring  instruments  have  had  notches 
formed  in  them  to  facilitate  their  action  upon  the  material  to  be 
bored.  These  notches  may  have  been  gradually  deepened  for  the 
same  purpose,  with  the  idea  that  the  deeper  they  were  the  more 
useful  they  would  become.  We  can  very  readily  conceive  that 

35 


36 


MODERN   LATHE   PRACTICE 


in  making  these  notches  the  tool  was  laid  on  its  side  and  gradu- 
ally revolved  as  the  notches  were  made,  beginning  at  the  point 
and  working  upwards  as  the  tool  was  revolved.  This  of  itself 
would  have  a  natural  tendency  to  produce  a  semblance  of  a  screw 
thread,  which  would  increase  the  efficiency  of  the  tool  by  drawing 
it  into  the  wood  to  be  bored.  When  this  tendency  was  noticed 
it  was  also  natural  to  see  why  it  acted  in  this  manner  and  to  in- 
crease this  action  by  more  carefully  making  these  notches.  In 
time  the  "worm  gimlet"  was  undoubtedly  evolved. 

The  form  of  a  screw  thread  having  once  been  arrived  at,  the 
realization  of  its  usefulness  for  various  purposes  was  only  a  ques- 
tion of  time.  It  is  altogether  probable,  however,  that  for  the 
purpose  of  holding  parts  of  a  machine  together,  or  for  similar 
mechanical  purpose,  screws  were  first  made  of  wood.  It  is  also 
pretty  certain  that  they  were  first  made  in  a  very  crude  form 
without  much  regard  to  the  exactness  of  the  pitch  or  form  of  the 
thread,  although  the  V-thread  would  be  the  most  natural  because 
the  most  simple  form.  It  is  also  generally  conceded,  of  course, 
that  they  were  made  by  hand  and  probably  with  the  rude  knives 
then  used,  as  hand  tools  were  the  only  ones  in  use. 

As  to  the  methods  used  in  making  the  first  nuts  for  use 
with  the  screws,  it  is  probable  that  they  were  quite  thin  as  com- 
pared with  the  pitch  of  the  thread,  possibly  containing  but  two 

or  three  complete  revolutions 
of  the  thread,  which  was 
worked  out  by  sharp-pointed 
instruments,  as  the  point  of 
the  knife  or  by  similar  means. 
This  method  may  have  led 
to  the  insertion  of  a  metal 
tooth  in  a  wooden  screw  and 
the  cutting  of  the  thread  in 
the  nut  in  this  manner.  We 
do  know  for  a  certainty  that  a  somewhat  similar  means  was  used 
many  years  later,  as  the  author  saw  a  device  such  as  is  represented 
in  Fig.  8,  which  was  preserved  as  a  curiosity,  representing  the 
early  mechanical  method  of  doing  this  work. 

This  device  consisted  of  a  turned  and  threaded  screw  D,  of 


FIG.  8.  —  Screw  Threading  or  Tapping 
Device  for  Wood. 


DEVELOPMENT  OF   THE   LATHE  37 

very  hard  wood,  having  one  end  turned  down  to  a  diameter  equal 
to  that  at  the  bottom  of  the  thread,  while  the  opposite  end  was 
made  much  larger  and  contained  a  hole  for  passing  a  bar  or  lever 
by  means  of  which  it  was  rotated.  At  the  termination  of  the  thread 
and  beginning  of  the  smaller  straight  portion  the  thread  was  cut 
away,  leaving  an  abrupt  termination,  and  at  this  point  was  inserted 
a  tooth  of  steel  formed  in  a  rough  manner  to  the  shape  of  the 
thread. 

In  a  wooden  nut  A  a  thread  had  already  been  cut,  by  some 
manner  unknown,  and  through  this  the  screw  D  was  fitted.  The 
piece  B,  to  be  tapped  or  threaded,  was  clamped  to  this  by  means 
of  the  steel  clamps  E,  E,  binding  the  two  firmly  together.  To  all 
appearances  the  tooth  or  cutter  d  could  be  set  in  or  out  so  as  to 
cut  merely  a  trace  of  the  thread  the  first  time  through,  then  an- 
other deeper  cut,  and  finally  finished  to  the  full  depth.  The  author 
had  no  means  of  ascertaining  the  origin  of  the  device,  but  the  wood 
of  which  it  was  composed  was  black  with  age  and  the  man  who 
possessed  it  could  not  tell  how  many  years  his  father  had  owned 
it  or  where  he  got  it.  It  was  certain,  however,  that  both  of  them 
had  been  mechanics  who  had  made  and  repaired  the  old-time 
wooden  spinning-wheels  in  which  a  wooden  screw  about  one  inch 
in  diameter  had  been  used  for  tightening  the  round  band  by  which 
the  twisting  mechanism  was  operated. 

Archimedes,  the  most  celebrated  of  the  ancient  mathematicians, 
certainly  had  a  good  idea  of  the  screw  thread,  as  is  shown  in  his 
famous  screw  made  of  a  pipe  wound  helically  around  a  rotating 
cylinder  with  which  he  raised  water  fully  two  hundred  years  before 
the  Christian  era.  Still  it  was  doubtless  a  long  time  after  this  period 
before  the  screw  was  constructed  so  as  to  be  applicable  to  the  uses 
of  the  present  day.  Of  the  progress  and  development  of  this  and 
other  similar  mechanical  matters  in  these  early  times  we  have 
little  authentic  information.  The  development  of  such  simple 
machines  as  the  lathe  preceded  much  that  was  mechanically 
important,  and  to  its  influence  we  owe  a  great  deal  of  the  early 
advancement  in  the  mechanic  arts. 

We  know  that  a  Frenchman  by  the  name  of  Jacques  Berson, 
in  1569,  built  a  lathe  that  seems  to  have  been  capable  of  cutting 
threads  on  wood.  An  engraving  of  his  lathe  is  given  in  Fig.  9. 


38 


MODERN   LATHE   PRACTICE 


As  will  be  seen  in  this  engraving  it  was  a  large,  clumsy  and  cum- 
bersome affair,  considering  the  work  it  was  designed  to  perform. 
While  the  various  parts  of  the  machine  are  not  very  clearly  shown, 
enough  is  given  to  show  us  that  he  had  a  wooden  lead  screw  to 
give  the  pitch  of  the  thread  by  means  of  a  half  nut  which  appears 
to  have  been  fixed  in  a  wooden  frame,  to  which  in  turn  the  piece 
to  be  threaded  was  attached  by  being  journaled  or  pivoted  upon 
it.  The  lead  screw  and  the  piece  to  be  threaded  were  both  re- 
volved by  means  of  cords  wound  around  spools  or  drums  upon  a 
shaft  overhead,  and  held  taut  by  weights  instead  of  the  flexible 
spring  pole  already  described.  These  cords  were  fastened  to  a 


FIG.  9.  —  Berson's  French  Lathe,  built  in  1569. 

vertically  sliding  frame,  also  balanced  by  cords  and  weights,  and 
to  which  was  attached  a  sort  of  stirrup  adapted  to  the  foot,  by 
which  the  machine  was  operated. 

Considering  the  early  time  at  which  this  lathe  was  constructed, 
it  shows  a  good  deal  of  ingenuity  and  may  well  have  been  the  fore- 
runner of  the  developments  in  this  line  which  came  after  it. 

It  is  a  matter  of  record  that  in  1680  a  mechanic  by  the  name 
of  Joseph  Moxan  built  lathes  in  England  and  sold  them  to  other 
mechanics,  but  we  do  not  possess  any  certain  or  authentic  knowl- 
edge of  their  design,  as  to  whether  or  not  screw  threads  could  be 
cut  with  them  or  whether  they  were  designed  for  work  on  wood 
or  metals,  or  both.  In  all  probability  they  were  foot  lathes  and 


DEVELOPMENT  OF  THE  LATHE  39 

used  on  all  materials  that  had  been  formed  in  a  lathe  up  to  that 
time. 

In  the  year  1772  the  French  encyclopedia  contained  the  illus- 
tration of  a  lathe  which  was  provided  with  a  crude  arrangement 
of  a  tool  block  or  device  for  holding  a  lathe  tool  and  adapting  it  to 
travel  in  line  with  the  lathe  centers.  By  this  it  would  seem  that 
the  inventor  had  some  idea  of  the  slide  rest  as  it  was  known  at  a 
later  day  by  its  invention  in  a  practical  form  by  John  Maudsley 
in  England,  in  the  year  1794.  Whether  Maudsley  had  seen  or 
heard  of  the  invention  shown  in  the  French  encyclopedia  or  not, 
it  would  seem  fair  to  assume  that  he  must  have  seen  that  or  some- 
thing akin  to  it,  as  the  twenty-two  years  elapsing  between  the  one 
date  and  the  other  must  have  served  to  make  the  earlier  invention 
comparatively  well  known  in  the  two  nearby  countries,  both  of 
which  contained,  even  at  this  early  day,  many  mechanics.  It  is 
interesting  to  observe  that  the  slide  rest  invented  by  Maudsley 
over  a  hundred  years  ago  has  been  so  little  changed  by  all  the 
improvements  since  made  in  this  class  of  machinery. 

There  seems  to  have  been  an  early  rivalry  between  the  French 
and  English  mechanics  in  the  development  of  machines  and  methods 
for  advancing  the  mechanic  arts!"  The  next  development  of  the 
screw-cutting  idea  seems  to  have  been  of  French  origin.  In  this 
lathe  there  was  an  arbor  upon  which  threads  of  different  pitches 
had  been  cut.  These  threads  were  on  short  sections  of  the  arbor 
and  by  its  use  the  different  pitches  required  could  be  cut.  While 
the  exact  manner  of  using  this  arbor  was  not  described,  its 
probable  method  of  use  will  readily  suggest  itself  to  the  mechanic, 
and  was,  no  doubt,  used  at  an  earlier  period,  and  in  fact  was  what 
led  up  to  the  use  of  a  lead  screw  or  arbor  with  a  multiplicity  of 
different  pitches.  The  principle  is  analogous  to  that  used  in  the 
"Fox"  brass  finishing  lathe  so  well  known  and  extensively  used, 
not  only  in  finishing  plain  surfaces  but  in  "  chasing  threads." 

This  machine  is  shown  in  Fig.  10,  which  is  a  perspective  view 
giving  all  the  essential  parts  of  the  mechanism.  The  head-stock 
A  and  tail-stock  B  are  of  the  usual  form  in  use  at  the  period,  and 
were  mounted  upon  the  wooden  bed  C  in  the  usual  manner.  The 
piece  D  to  be  threaded,  and  an  equal  length  of  lead  screw  or  "  master 
screw,"  as  it  was  then  called,  were  placed  end  to  end  in  the  lathe, 


40  MODERN   LATHE  PRACTICE 

the  outer  ends  held  in  the  lathe  centers,  and  their  inner  ends,  evi- 
dently fixed  to  each  other  by  a  clutch  of  some  kind,  were  supported 
by  a  kind  of  center  rest  F.  Fixed  to  the  front  of  the  bed  C  was  a 
cast  iron  supporting  bar  G,  of  T-shaped  section,  extending  nearly  the 
entire  length  of  the  lathe  bed.  Upon  the  bar  G,  the  top  of  which 
was  of  dovetail  form,  was  fitted  the  carriage  H,  which  was  adapted 
to  slide  upon  it  and  to  support  a  thread-cutting  tool  J,  and  a  tool 
or  " leader"  K,  which  fitted  into  the  thread  of  the  "master  screw" 
E,  and  served  the  same  purpose  as  the  lead  screw  nut  of  the  present 
day.  Evidently  the  operation  was  that  by  revolving  the  piece  D 
the  "master  screw"  E  was  also  rotated,  and  this  rotation  of  the 


FIG.  10.  —  Thread-Cutting  Machine  using  a  "Master  Screw." 

threaded  screw,  acting  upon  the  "leader"  K,  forced  the  carriage 
H  forward,  causing  the  thread-cutting  tool  J  to  cut  a  thread  upon 
the  piece  D,  of  a  pitch  equal  to  that  upon  the  "master  screw"  E. 
It  is  probable  that  no  better  means  of  adjusting  the  thread-cutting 
tool  J  was  provided  than  setting  it  in  by  light  blows  of  the  hammer. 
While  the  threads  thus  cut  were  probably  rather  poor  specimens 
of  mechanical  work,  they  answered  the  requirements  of  the  times, 
and  as  usual  better  means  were  devised  for  making  them  as  the 
need  of  better  and  more  accurate  work  created  new  demands  and 
a  higher  standard  of  workmanship. 

As  will  be  seen  in  the  above  example  the  idea  of  the  slide-rest 
is  used.    In  this  case  some  such  device  was  a  necessity.    Doubtless 


DEVELOPMENT  OF  THE  LATHE  41 

threads  had  been  cut  with  some  sort  of  a  "  chaser,"  or  tool  with 
notches  shaped  to  the  form  and  pitch  of  the  thread.  These  were 
very  extensively  used  later  and  for  many  years  in  brass  work,  and 
the  old-time  machinist  was  very  expert  in  their  use.  The  slide- 
rest,  as  we  know  it,  while  it  relieved  the  workman  from  the  fatigue 
of  holding  the  tool  firmly  in  his  hands  and  depending  entirely 
upon  them  for  the  position  of  the  tool,  with  the  exception  of  such 
support  as  the  fixed  rest  gave  him,  was  comparatively  slow  in 
coming  into  general  use.  While  its  usefulness  must  have  been 
apparent  to  the  average  mechanic,  the  conservative  ideas  then  in 
vogue  must  have  retarded  its  prompt  adoption,  as  they  did  many 
other  meretorious  inventions. 

By  the  use  of  the  device  shown  in  Fig,  10,  it  is  plain  that  a 
different  " master  screw"  was  needed  for  each  different  pitch  of 
thread  to  be  cut,  although  the  diameter  of  the  work  might  be  any- 
thing within  the  range  of  the  lathe  to  hold  and  drive,  so  that  pro- 
vision was  made  for  supporting  the  inner  ends  of  the  piece  to  be 
cut  and  the  " master  screw,"  and  for  driving  the  latter  by  the 
former.  The  idea  of  driving  the  "master  screw  "  or  lead  screw  at 
a  different  speed  from  that  of  the  piece  to  be  threaded  had  not  yet 
been  thought  of,  and  it  was  years  before  this  development  took 
place. 

But  before  proceeding  to  this  phase  of  the  development  of 
thread  cutting,  and  consequently  with  the  further  development  of 
the  lathe,  let  us  look  a  little  farther  into  the  methods  of  generating 
threads.  That  is,  of  producing  the  "master  screw,"  from  which 
other  screws  might  be  made. 

The  author  well  remembers  during  his  boyhood  an  old  curi- 
osity shop  out  in  the  country  in  which  various  kinds  of  hand 
machines  were  made  and  repaired.  Among  other  things  made 
were  various  appliances  and  devices  for  spinning  woolen  yarn  and 
reeling  it  up  into  skeins  of  forty  threads  to  a  "knot,"  as  it  was 
called.  To  furnish  an  automatic  counter  for  this  reel  a  worm- 
gear  of  forty  teeth  was  used  which  engaged  with  a  single  threaded 
worm  on  the  reel-shaft.  Both  the  shaft  having  the  worm  formed 
upon  it  and  the  worm-wheel  were  of  wood,  usually  oak  or  maple, 
and  the  thread  was  formed  by  wrapping  a  piece  of  paper  around 
the  turned  shaft  and  cutting  through  this  with  a  knife  so  as  to 


42  MODERN   LATHE   PRACTICE 

make  its  length  equal  to  the  circumference  of  the  shaft,  its  width 
representing  the  longitudinal  distance  on  the  shaft.  This  piece 
of  paper  was  then  divided  into  equal  parts  at  each  end  and  in- 
clined lines  drawn  upon  it  as  shown  in  Fig.  11,  the  divisions  being 
equal  to  the  pitch  of  the  thread,  found  by  spacing  the  circumference 
of  the  worm-gear  blank  for  the  forty  teeth.  The 
paper  was  then  glued  around  the  shaft  and  the 
diagonal  lines  gave  the  correct  development  of 
the  screw  thread,  which  was  worked  out  with  a  fine 
saw,  a  chisel,  or  knife,  and  a  triangular  file.  The 
teeth  of  the  worm-gear  were  similarly  cut  to  the 
proper  V-shape,  and  the  result  was  a  perfectly  prac- 
tical and  really  workmanlike  piece  of  mechanism  that 
Thread  be-  answered  the  purpose  remarkably  well. 


same  method  of  laying  off  screw  threads 
was  in  practical  use  many  years  ago  and  was  used 
by  one  Anthony  Robinson  in  England  as  early  as  the  year  1783, 
at  which  time  it  is  recorded  of  him  that  he  made  a  triple-threaded 
screw  6  inches  in  diameter  and  7  feet  6  inches  in  length.  It  is 
said  that  he  first  laid  off  one  thread  by  the  method  above  de- 
scribed, leaving  a  sufficient  space  between  the  convolutions  for  the 
other  two  threads.  This  first  thread  was  then  worked  out  by 
hand  with  the  time-honored  hammer,  chisel,  and  file,  and  he  after- 
wards used  this  thread  as  a  guide  for  making  the  other  two  by 
the  same  primitive  means. 

In  the  light  of  the  present  facilities  for  cutting  threads  this 
process  seems  most  tedious  and  laborious,  and  yet  much  of  the 
machinist's  work  of  that  time  was  equally  slow  and  must  have 
sorely  taxed  the  patience  of  the  workman,  whose  principal  and 
often  only  machine  was  a  lathe  of  very  crude  design  and  work- 
manship, and  in  which  he  managed  to  do  not  only  turning  and  bor- 
ing but  slotting,  splining,  milling,  gear-cutting,  and  an  endless  variety 
of  similar  jobs,  and  in  lieu  of  a  planer  having  recourse  to  his  ever 
ready  cold  chisel,  hammer,  and  file,  which  with  a  straight-edge  en- 
abled him  to  make  many  a  flat  surface  of  remarkable  nicety  con- 
sidering his  limited  facilities.  And  from  these  pioneer  machinist's 
came  the  American  machinist  of  to-day,  the  most  thorough,  best 
educated  and  expert  mechanic  the  world  has  ever  seen. 


DEVELOPMENT  OF  THE  LATHE 


43 


FIG.  12.  —  End  Elevation  of 
"Chain  Lathe." 


It  will  doubtless  have  been  noticed  that  in  the  earlier  examples 
of  the  lathe,  as  in  most  of  the  machines  in  use,  the  framework  of 
the  machine  in  the  lathe,  the  bed,  and  legs,  were  made  of  wood 
with  the  various  metal  parts  se- 
cured to  them.  A  good  example 
of  this  method  of  construction, 
as  well  as  the  general  construc- 
tion of  the  lathes  of  the  date 
when  this  one  was  built,  is  shown 
in  front  end  elevation  in  Fig.  12, 
and  in  front  elevation  in  Fig.  13. 
The  history  of  this  lathe  is  well 
known  to  the  author,  who  was 
well  acquainted  with  the  old 
Scotchman,  one  John  Rea,  who 
had  a  small  machine  shop,  wood 
shop,  iron  foundry,  and  sawmill 
in  East  Beekmantown,  Clinton 
County,  New  York  State,  during  and  for  many  years  prior  to  the 
civil  war. 

This  lathe  had,  as  will  be  seen  by  an  inspection  of  the  drawings, 
a  bed  composed  of  two  timbers,  placed  at  the  proper  distance  apart 
and  supported  upon  wooden  legs,  which  in  turn  rested  upon  a  cross 
timber  supported  by  the  floor.  The  timbers  were  of  hard  maple, 
those  forming  the  bed  being  about  5  inches  thick  and  12  inches 
deep  and  were  about  15  feet  long.  The  lathe  would  swing  about 
32  inches  over  the  bed.  The  patterns  were  made  by  Mr.  Rea,  the 
castings  made  in  his  foundry,  and  the  machine  work  done  in  the 
nearby  village  of  Plattsburgh. 

The  "ways"  or  V's  of  the  lathe  were  of  wrought  iron  about 
f  x3  inches  let  into  a  " rabbit"  cut  on  the  inside  edges  of  the 
timbers  forming  the  bed,  and  fastened  by  large  wood  screws. 
The  top  edges  of  these  iron  strips  were  chipped  and  filed  to  an  angle 
of  about  45  degrees  to  the  sides,  thus  making  the  V  an  angle  of 
about  90  degrees.  The  head-stock  had  cast  in  it  square  pockets 
in  which  the  boxes  for  the  main  spindle  were  fitted  by  filing,  and 
were  held  down  by  a  rough  wrought  iron  cap  through  which  passed 
two  threaded  iron  studs  which  had  been  cast  into  the  metal.  Upon 


44 


MODERN   LATHE  PRACTICE 


these  were  two  nuts  as  shown.  The  main  spindle  was  of  wrought 
iron  and  carried  a  wooden  cone  pulley  built  up  on  cast  iron  flanges 
keyed  to  the  spindle.  There  were  no  back  gears. 

The  carriage  was  of  the  roughest  description  and  had  a  hand 
cross  feed  for  the  tool  block,  which  carried  the  old-fashioned  tool- 

I,;,  clamping  device  held  in 
place  by  studs  and  nuts. 
The  longitudinal  hand  feed 
was  by  means  of  a  crank- 
shaft and  pinion  with  cast 
teeth  and  a  rack  similarly 
formed,  fastened  to  the 
front  of  the  bed  by  wood 
screws.  The  longitudinal 
powrer  feed  was  by  means 
of  an  ordinary  iron  chain 
(hence  the  common  name  of 
" chain  lathe"  given  to  a 
lathe  having  this  method  of 
feeding).  This  chain  ran 
over  a  very  clumsy  form  of 
sprocket-wheel  made  some- 
what  similar  to  those  used 
in  chain  hoists  of  the  pres- 
ent  day.  At  the  head  end 
of  the  lathe  this  sprocket- 
wheel  was  fixed  upon  a 
shaft  which  carried  on  its 
front  end  a  very  crude  form 
of  a  worm-wheel  arranged 
to  engage  with  an  equally 
crude  worm  upon  a  shaft 
journaled  in  boxes  at  the 
front  of  the  bed,  one  of 
which  was  pivoted  to  the  front  of  the  bed  and  the  other  capable  of 
sliding  vertically  and  therefore  making  provision  for  dropping  this 
worm  out  of  contact  with  the  worm-gear  when  it  was  desired  to 
"  throw  out  the  feed."  To  keep  this  feeding  mechanism  in  gear  a 


DEVELOPMENT  OF  THE  LATHE  45 

lever  was  pivoted  upon  the  front  side  of  the  lathe  bed,  one  end 
connected  with  the  sliding  box  of  the  worm-gear  shaft  and  the 
other  hooked  under  a  pin  driven  into  the  front  of  the  lathe  bed,  as 
shown  in  the  engraving. 

This  worm-shaft  was  driven  by  a  round  leather  belt  working 
in  one  of  the  grooves  of  a  three-step  cone  pulley  fixed  upon  it, 
and  extending  up  to  a  similar  three-step  cone  pulley  fixed  upon  the 
rear  end  of  the  main  spindle.  These  pulleys  were  of  hard  wood  and 
attached  to  cast  iron  flanges  fixed  in  place.  The  belt  was  a  "  home- 
made" production  but  very  much  resembling  the  best  twisted 
round  leather  belts  of  the  present  day,  and  was  about  three  quarters 
of  an  inch  in  diameter. 

The  belt  on  the  cone  pulley  upon  the  main  spindle  was  about 
three  and  a  half  inches  wide,  the  large  step  on  the  cone  being  about 
twenty  inches  in  diameter. 

It  will  be  noticed  that  no  provisions  was  made  in  this  lathe  for 
cutting  left-hand  threads.  It  seems  altogether  probable  that  the 
use  of  left-hand  threads  began  many  years  after  right-hand  threads 
were  developed  and  used,  as  the  need  of  them  no  doubt  did  not  exist 
until  the  mechanical  arts  were  much  farther  advanced  and  possibly 
not  until  they  were  wanted  for  producing  a  contrary  motion  in 
devices  using  the  worm  and  worm  gear. 

The  tail-stock  was  of  very  simple  construction,  as  will  be 
seen  in  the  engraving,  the  tail  spindle  having  formed  upon  its  rear 
end  a  downwardly  projecting  arm  which  embraced  a  screw  tapped 
into  the  main  casting  and  being  provided  with  a  crank  by  which 
it  was  operated.  To  bind  the  spindle  in  any  desired  position  a 
ring  was  provided,  through  which  the  tail  spindle  passed,  and  to 
which  was  welded  a  bolt  end  passing  up  through  the  casting  and 
being  provided  with  a  lever  nut  as  shown.  It  will  be  noticed  that 
by  this  construction  the  operation  of  binding  or  clamping  the  tail 
spindle  tended  to  raise  it  out  of  its  true  bearing  position  and  hold 
it  suspended  by  this  binder  and  its  contact  with  the  top  surfaces 
of  the  holes  through  which  it  passed  in  the  main  casting.  This 
continued  to  be  the  practice  for  clamping  a  tail  spindle  for  many 
years  before  the  present  method  of  splitting  the  bearing  at  the 
front  and  fastening  it  by  a  clamping  screw  was  first  used. 

The  lead  screw  was  placed  at  the  back  of  the  lathe  and  had 


46  MODERN   LATHE   PRACTICE 

fitted  upon  it  a  curved  forging,  carrying  a  solid  nut  and  capable 
of  being  attached  to  the  carriage  by  two  bolts  when  it  was  desired 
to  cut  threads.  This  forging  was  frequently  called  a  " goose  neck," 
from  its  peculiar  curved  shape.  The  thread  of  the  lead  screws  was 
square  and  four  threads  to  the  inch.  It  was,  of  course,  made  of 
wrought  iron,  the  use  of  steel  for  this  purpose  being  of  much  later 
date. 

The  method  of  driving  the  lead  screws  was  characteristic 
and  peculiar  and  is  one  of  the  main  reasons  for  introducing  this 
lathe  to  the  attention  of  the  readers  of  this  book,  as  it  marks  one 
of  the  first  known  methods  of  changing  the  ratio  of  speed  between 
the  main  spindle  and  the  lead  screw  by  means  of  gears  of  a  varying 
number  of  teeth,  which  is  here  done  in  a  very  crude  but  compara- 
tively effective  manner.  This  method  was  as  follows:  Upon  the 
rear  end  of  the  main  spindle  was  fixed  a  flange  having  in  its  face  a 
series  of  pins  which  formed  the  teeth  of  a  " crown  gear"  and  which 
engaged  with  a  "  Ian  tern  pinion"  fixed  upon  an  inclined  shaft 
journaled  in  a  bracket  fixed  to  the  lathe  head  and  lining  with  the 
lead  screw.  This  lantern  pinion  was  made  of  two  heads  fitted 
upon  the  shaft  and  having  pins  running  through  the  heads  in  a  line 
parallel  with  the  axis  of  the  shaft,  similar  to  the  method  seen  in  a 
brass  clock. 

Upon  the  lead  screw  was  a  crown  wheel  similar  to  that  upon  the 
rear  end  of  the  main  spindle,  and  whose  pins,  or  teeth,  engaged 
with  those  formed  by  the  pins  or  rods  in  the  lantern  pinion  upon 
the  lower  end  of  the  inclined  shaft.  The  fact  that  this  lantern 
pinion  was  of  much  greater  length  than  that  on  the  upper  end  would 
seem  to  indicate  that  the  designer  or  builder  of  the  lathe  had  in- 
tended to  use  different  sized  wheels  on  the  end  of  the  lead  screw 
for  the  purpose  of  producing  different  ratios  between  the  speed 
of  the  lead  screw  and  that  of  the  main  spindle,  and  therefore  to 
cut  threads  of  differing  pitches.  This  seems  to  have  been  the 
earliest  method  of  producing  this  result  by  a  change  of  gearing,  and 
probably  antedated  the  method  of  using  differing  diameters  of 
spur  gears,  as  it  is  well  known  that  the  crown  wheel  or  pin  gear 
and  lantern  pinion  were  the  oldest  form  of  gearing,  and  in  use  in 
Egypt  at  a  very  early  date,  and  that  an  imitation  of  our  spur  gear 
was  made  in  a  similar  manner  by  inserting  the  pins  in  the  periphery 


DEVELOPMENT  OF  THE  LATHE 


47 


of  the  wheel  instead  of  its  face.  The  builder  of  the  lathe  in  ques- 
tion probably  borrowed  his  idea  from  some  lathes  very  much  older 
and  which  he  had  seen  in  his  native  country,  as  regular  spur  gearing 
for  the  same  purpose  had  been  used  at  a  considerably  earlier  date 
than  the  building  of  his  lathe,  and  as  he  was  a  man  past  middle  life 
at  that  time.  The  lathe  was  built  about  1830  and  was  in  active 
service  as  late  as  1875,  although  the  lantern  pinions  and  pin  gears 
had  been  discarded  and  hung  up  on  the  walls  of  the  old  shop,  and 
in  their  place  were  the  usual  spur  gears,  and  a  stud  plate  had  been 
added  for  the  purpose  of  carrying  an  idle  gear  so  as  to  accommodate 


FIG.  14.  —  Putnam  Lathe  built  in  1836. 

different  sizes  of  change  gears,  and  a  second  idler  when  left-hand 
threads  were  to  be  cut.  Otherwise  the  old  lathe  remained  as  it 
was  originally  built. 

The  transition  from  wooden  to  iron  beds  and  legs  for  lathes 
was  probably  made  by  the  early  builders  of  these  machines  about 
1840  or  a  few  years  later.  It  is  certain  that  in  1850  lathes  with 
iron  beds  were  made  in  New  Haven,  Conn.,  and  that  from  this 
time  on  iron  was  universally  used  for  this  purpose. 

A  good  example  of  these  lathes  built  about  the  time  of  the 
from  wood  to  iron  beds  is  furnished  in  Fig.  14,  of  one  of 


48  MODERN   LATHE   PRACTICE 

the  lathes  built  by  J.  &  S.  W.  Putnam,  in  Fitchburg,  Mass.,  about 
the  year  1836,  or  somewhat  earlier,  and  shows  in  a  remarkably 
sharp  contrast  with  those  of  the  present  day  when  all  possible 
devices  are  adopted  for  powerful  drives,  rapid  change  gear  devices 
for  both  feeding  and  for  thread  cutting,  to  the  common  inch  stand- 
ard and  those  measured  by  the  metric  system;  with  micrometer 
gages  and  stops;  with  turrets  located  upon  the  bed  or  upon  the 
carriage;  and  with  all  manner  of  attachments  and  accessories  for 
doing  a  great  and  almost  endless  variety  of  extremely  accurate 
work,  as  well  as  for  turning  out  an  immense  quantity  of  it. 

One  other  example  of  the  early  lathes  is  shown  that  was  in 
some  respect  somewhat  ahead  of  its  time,  as  will  be  pointed  out. 
It  is  a  20-inch  swing  lathe  built  by  A.  M.  Freeland,  in  New  York 
City,  in  1853.  It  is  shown  in  Fig.  15.  It  is  said  that  Mr.  Freeland 


FIG.  15.  —  Freeland  Lathe  built  in  1853. 


used  English  machines  as  his  models  and  was  an  admirer  of  Whit- 
worth  and  his  ideals  of  what  machine  tools  should  be.  In  this 
lathe  the  flat-top  bed  is  used  as  in  many  English  and  some  very 
good  American  lathes  at  the  present  time.  It  will  be  noticed  that 
the  apron  is  in  a  somewhat  abbreviated  form,  only  sufficient  to 
support  its  very  simple  operative  mechanism. 

The  carriage  carried  a  cross-slide  upon  which  were  two  tool-posts, 
one  in  front  and  one  in  the  rear,  which  were  connected  by  a  right 
and  left  cross-feed  screw,  while  there  was  a  short  supplemental 
screw  for  adjusting  the  back  tool  independently  of  the  front  one, 
and  also  a  longitudinal  screw  for  adjusting  the  tool  lengthwise  of 
the  work  being  turned,  so  that  the  second  or  back  tool  would  cut  a 
portion  of  the  feed,  as  the  roughing  cut  and  the  front  one  take  the 
remainder.  It  will  be  understood  that  the  back  tool  is  used  upside 
down  as  in  the  modern  lathes  carrying  the  second  tool. 


DEVELOPMENT  OF  THE  LATHE  49 

There  was  no  rack  and  pinion  arrangement  for  lateral  hand  feed 
for  the  carriage,  the  lead  screw  being  used  for  this  purpose  by 
engaging  with  its  thread  a  pinion  fixed  to  the  shaft  operated  by 
the  crank  at  the  right-hand  end  of  the  apron. 

It  will  be  noticed  that  the  driving-cone  on  the  spindle  has  five 
steps,  as  in  a  modern  lathe.  The  bed  seems  so  light  that  it  would 
now  be  called  frail,  in  view  of  the  present  duty  expected  of  a  lathe 
of  this  swing,  and  in  sharp  contrast  with  the  massive  beds  now 
used. 

In  future  chapters  will  be  shown  the  modern  American  lathes 
with  all  their  peculiar  features  illustrated,  explained,  and  com- 
mented upon  as  this  work  progresses,  taking  up,  not  only  the  regu- 
lar types  of  engine  lathes,  but  also  those  of  a  more  special  nature 
such  as  turret  lathes,  pattern  lathes,  bench  lathes,  high-speed  lathes, 
gap  lathes,  forming  lathes,  precision  lathes,  multiple  spindle  lathes, 
and  so  on,  including  lathes  driven  with  belts  from  a  countershaft 
in  the  usual  manner,  and  also  those  driven  by  electric  motors 
with  the  most  modern  appliances. 

In  illustrating  and  describing  these  lathes  much  care  has  been 
exercised  to  have  both  the  illustration  and  the  description  correct 
as  to  the  facts  shown  and  commented  upon,  and  to  this  end  the 
builders  themselves  have  furnished  the  necessary  facts  so  that  the 
statements  herein  given  are  from  proper  authority  and  may  be 
relied  upon  in  considering  the  proper  selection  of  the  lathe  best 
suited  for  the  work  for  which  it  is  to  be  purchased. 


CHAPTER  III 

CLASSIFICATION   OF   LATHES 

The  essential  elements  of  a  lathe.  The  bed.  The  head-stock.  The  tail- 
stock.  The  carriage.  The  apron.  The  turning  and  supporting  rests. 
The  countershaft,  Taper  attachments.  Change-gears.  Classification 
applied  to  materials,  labor  accounts,  and  the  handling  of  parts  in  the 
manufacture  of  lathes.  The  four  general  classes  of  lathes.  The  eighteen 
sub-divisions  of  these  classes.  The  first  class:  hand  lathes,  polishing 
lathes,  pattern  lathes,  spinning  lathes  and  chucking  lathes.  The  second 
class:  engine  lathes  without  thread-cutting  mechanism,  Fox  brass  lathes, 
forge  lathes,  and  roughing  lathes.  The  third  class:  complete  engine 
lathes  with  thread-cutting  mechanism,  precision  lathes,  rapid  reduction 
lathes,  and  gap  lathes.  The  fourth  class :  forming  lathes,  pulley  lathes, 
shafting  lathes,  turret  lathes  and  multiple  spindle  lathes.  Rapid  change 
gear  devices.  Bancroft  and  Sellers  device.  The  Norton  device.  Lathe 
bed  supports.  The  precision  lathe.  The  rapid  production  lathe.  The 
gap  lathe.  Special  lathes.  Forming  lathes.  Pulley  lathes.  Shafting 
lathes.  Turret  lathes.  Screw  machines.  Multiple  spindle  lathes. 
Variety  of  special  lathes. 

IN  considering  what  are  the  essential  elements  of  a  lathe  they 
may  be  briefly  stated,  if  we  assume  that  in  a  simple  lathe  the  work 
is  to  be  what  was  originally  intended,  that  is,  held  on  centers,  and 
may  be  stated  in  these  terms,  viz.  The  essential  elements  of  a 
simple  metal  turning  lathe  are :  suitable  means  for  supporting  and 
holding  the  work  upon  centers;  proper  mechanism  for  rotating  the 
work;  and  a  cutting-tool  properly  held  and  supported  upon  a 
traveling  device  actuated  by  suitable  mechanism. 

The  first  of  these  essentials  comprise  the  bed,  head-stock,  and 
tail-stock,  with  their  proper  parts  and  appendages,  so  far  as  the 
fixed  parts  and  centers  are  concerned,  and  including  legs  or  other 
supports  for  the  bed.  The  second  essential  comprises  the  driving 
mechanism,  consisting  of  the  driving-cone,  back  gearing,  etc.,  and 
the  third  essential  consisting  of  the  carriage,  tool  block,  and  cutting- 
tool,  with  the  necessary  gearing  for  moving  it,  and  the  connecting 

50 


CLASSIFICATION  OF  LATHES  51 

parts  for  transmitting  power  for  that  purpose  from  the  main 
spindle  of  the  lathe. 

This  classification  of  the  essential  elements  of  the  lathe  naturally 
suggests  certain  groups  of  related  parts  which  compose  a  complete 
lathe,  and  correspond  with  the  experience  and  practice  of  the 
author  in  the  designing  and  construction  of  the  various  types  of 
lathes.  They  are  as  follows : 

1.  Bed  and  appendages,  including  the  legs  or  cabinets,  lead- 
screw  and  its  boxes,  the  feed-rod,  its  boxes  and  supports,  carriage 
rack,  tail-stock,  moving  rack  (when  the  lathe  is  large  enough  to 
require  one),  stud-plate  and  studs,  and  such  necessary  bolt,s  and 
screws  as  are  needed  to  fasten  these  parts. 

2.  Head-stock  and  appendages,  including  such  feed-gears  as 
are  necessary  to  connect  with  the  feed-rod  in  case  of  a  geared  feed. 
Also  the  holding-down  bolts  and  binders  (if  used),  for  fastening 
the  head-stock  to  the  bed,  and  the  large  and  small  face-plates. 
(Where  a  quick  change  gear  device  is  used  and  is  not  an  integral 
part  of  the  bed  or  head  it  forms  a  separate  class.) 

3.  Tail-stock   and  appendages,   such  as  holding-down  bolts, 
binders,  and,  when  the  lathe  is  large  enough  to  require  it,  the  mover 
bracket,  gears,  shafts  and  crank;  and  if  the  tail-spindle  is  handled 
by  a  hand-wheel  in  front,  the  brackets,  shafts,  spur  and  bevel 
gears,  etc. 

4.  Carriage  and  appendages,  including  gibs  and  a  solid  tool 
block  if  one  is  used,  but  not  a  compound  rest  where  these  are 
furnished  at  the  order  of  the  purchaser.     If  the  lathes  are  habitually 
built  with  compound  rests  they  may  be  classed  with  the  carriage. 

5.  Apron  and  appendages,  including  the  apron  in  its  complete 
assembled  form  ready  to  attach  to  the  carriage,  together  with  the 
screws  for  making  such  attachment. 

6.  Rests,  including    the  compound   rest   (when   not   classed 
with  the  carriage,  the  full  swing,  pulley  or  wing  rest  (as  it  is  vari- 
ously named),   center    rest,  back  rest,  (when  one  is  furnished), 
together  with  bolts,  binders,  and  similar  means  of  attachment. 

7.  Countershaft  and  its  appendages,  including  the  hangers, 
boxes,  shipper  rod,  etc.,  and  any  similar  parts  for  tight  and  loose 
pulleys  or  friction  pulleys  as  may  be  necessary  to  make  it  complete 
and  ready  to  put  up. 


52 


MODERN  LATHE   PRACTICE 


Taper  attachments,  special  tool  holders,  or  tool-rests,  and  all 
similar  parts  are  deemed  extras  and  not  included  in  regular  lists. 

Change-gears  are  sometimes  listed  as  a  part  of  the  bed  and 
appendages.  When  these  are  a  part  of  a  special  quick  change 
device  they  are  made  a  separate  class.  This  is  understood  to  be 
when  the  change  gear  device  is  detachable.  When  made  a  part 
of  the  head-stock  or  the  bed  such  parts  as  are  attached  to  the  one 
or  the  other  of  these  main  parts  will  be  listed  with  it  and  become 
a  portion  of  its  appendages. 

This  classification  is  carried  into  all  lists  of  materials  of  what- 
ever kind  and  into  all  accounts  of  labor  in  the  designing,  construct- 
ing, and  handling  of  these  parts,  whether  in  groups  or  as  single 
pieces,  during  their  progress  through  the  various  departments  of 
the  shop. 

The  classification  of  these  lathes  as  entire  and  complete  ma- 
chines, and  according  to  their  various  types  of  design  and  con- 
struction and  the  uses  to  which  they  are  to  be  put,  will  be  next 
considered,  and  in  so  doing  it  seems  appropriate  to  commence  with 
the  more  simple  forms,  and  to  proceed  with  such  types  as  are  com- 
monly recognized  and  in  use  at  the  present  time,  dividing  them 
into  four  general  classes  and  these  into  such  sub-divisions  as  their 
construction  and  uses  seem  to  demand  By  this  method  of  classi- 
fication we  shall  have: 


FIRST 
SPEED  LATHES. 


SECOND 

METAL  TURNING 
LATHES. 

THIRD 
ENGINE  LATHES. 


FOURTH 
SPECIAL  LATHES. 


Hand  Lathes,  for  floor  or  bench. 

Polishing  Lathes. 

Pattern  Lathes. 

Spinning  Lathes. 

Chucking  Lathes,  with  or  without  a  turret. 

Engine  Lathes,  without  thread-cutting  mechanism. 

Fox  Brass  Lathes. 

Forge  Lathes. 

Roughing  Lathes. 

Complete  Engine  Lathes  with  thread-cutting  mechanism. 

Precision  Lathes. 

Rapid-Reduction  Lathes. 

Gap  Lathes. 

Forming  Lathes. 

Pulley  Lathes. 

Shafting  Lathes. 

Multiple  Spindle  Lathes. 

Turret  Lathes. 


CLASSIFICATION   OF   LATHES 


53 


In  the  first  class  we  understand  by  speed  lathes  a  lathe 
without  back  gears  and  without  the  carriage  and  apron  of  an 
engine  lathe,  although  as  chucking  lathes  they  may  be  provided 
with  back  gears,  as  they  are  frequently  used  for  boring  quite  large 
holes,  and  are  therefore  made  much  larger  and  heavier  than  those 
of  the  other  sub-divisions  of  this  class. 

Hand  lathes  are  supposed  to  be  for  the  usual  operations  of  hand 
tool  turning,  filing  and  light  metal  turning  by  means  of  a  detach- 
able slide-rest.  They  may  have  legs  of  sufficient  height  to  support 
them  from  the  floor  as  in  Fig.  16,  or  with  very  short  legs,  making 


FIG.  16.  —  A  Hand  Lathe. 

them  convenient  for  setting  upon  the  usual  machinists'  bench  as 
in  Fig.  17.  Otherwise  their  design  and  construction  is  the  same. 

Polishing  lathes  are,  as  their  name  implies,  mostly  used  for 
polishing  cylindrical  work,  although  a  hand-rest  or  a  slide-rest  is 
sometimes  used  upon  them. 

Pattern  lathes,  as  shown  in  Fig.  18,  are  usually  so  called  when 
used  by  wood  pattern-makers  and  while  usually  used  with  hand 
tools,  as  chisels  and  gouges  with  the  support  of  a  hand-rest,  at  the 
present  time  a  majority  of  them  are  provided  with  a  slide-rest. 


54 


MODERN   LATHE   PRACTICE 


Those  of  larger  swing  have  the  rear  end  of  the  main  spindle  threaded 
for  attaching  a  face-plate  upon  which  is  fixed  large  face-plate  work 
of  too  great  a  diameter  to  be  turned  on  the  ordinary  face-plate,  as 
this  supplemental  face-plate  overhangs  the  end  of  the  bed  and 
consequently  the  diameter  of  the  work  that  can  be  turned  is  only 
limited  by  the  height  of  the  main  spindle  above  the  floor.  In  this 


FIG.  17.  —A  Bench  Lathe. 

class  of  work  a  hand-rest  is  supported  by  a  tripod  stand  that  may 
be  moved  to  any  desired  position  on  the  floor  and  is  heavy  enough 
to  stand  steadily  wherever  it  may  be  placed. 

Spinning  lathes  are  used  for  forming  a  great  variety  of  shapes 
from  discs  of  quite  thin  metal,  usually  brass,  with  various  shaped 

tools  held  either  by  hand  or  in 
the  tool  post  of  a  slide-rest. 
These  tools  form  the  metal  in  a 
manner  similar  to  the  action  of 
a  burnisher  instead  of  cutting  it, 
usually  over  a  former,  by  which 
the  same  shape  is  produced  in 
all  the  pieces.  Such  work  is 
not  usually  of  large  diameter, 
therefore  a  spinning  lathe  is 
generally  of  small  and  medium  swing  and  is  of  substantially  the 
same  construction  as  the  ordinary  hand  lathe,  except  when  built 
for  large  or  special  work. 

Chucking  lathes,  shown  in  Fig.  19,  are  used  to  a  great  extent 
for  boring  and  reaming  circular  castings,  as  pulleys,  gears,  hand- 
wheels,  balance-wheels,  sleeves,  bushings,  flanges,  and  all  similar 
work  that  require  only  the  formation  of  the  hole,  although  some 


FIG.  18.  —  A  Pattern  Lathe. 


CLASSIFICATION   OF  LATHES 


55 


of  these  machines  are  provided  with  a  cross-slide  and  tool-post  by 
means  of  which  the  hubs  or  bosses  of  the  work  may  be  faced.  Many 
of  them  are  now  provided  with  a  turret,  by  means  of  which  several 
tools  may  be  carried  so  that  not  only  boring  and  reaming,  but 
recessing,  facing,  etc.,  may  also  be  done  without  removing  the 
work  from  the  chuck.  These  lathes  usually  have  a  very  large 
driving-cone  with  a  broad  belt  surface,  or  they  are  constructed 
with  back  gears  similar  to  those  in  an  engine  lathe.  It  was  from 
this  form  of  lathe  that  the  elaborate  lathes  built  by  Jones  &  Lam- 
son  and  others  of  similar  design  and  construction  originated. 


FIG.  19.  —  A  Chucking  or  Turret  Head  Lathe. 

In  the  second  class  we  have  what  used  to  be  called  the  "  plain 
engine  lathe,"  that  is,  one  not  provided  with  any  thread-cutting 
mechanism.  Formerly  the  smaller  sizes  of  these  lathes  did  not 
usually  have  the  power  cross-feed,  although  at  the  present  time 
there  are  very  few  of  them  built  by  any  of  the  manufacturers,  unless 
by  a  special  order,  practically  all  the  modern  engine  lathes  having 
the  thread-cutting  mechanism,  and  frequently  it  is  made  an  elabo- 
rate and  expensive  feature  and  covers  a  wide  range  of  work.  When 
these  lathes  were  built  to  a  considerable  extent  the  feeding  mechan- 
ism was  nearly  always  driven  by  a  belt,  gears  being  very  seldom 
used  for  this  purpose.  No  sub-division  has  been  here  given  for 
foot-power  lathes,  as  any  of  those  so  far  described  can  and  have 
been  operated  by  foot-power  when  not  too  large  to  be  thus  driven. 


56 


MODERN  LATHE   PRACTICE 


The  Fox  brass  lathe,  Fig.  20,  is  built  upon  similar  lines  as  the 
engine  lathe  without  a  carriage  or  apron,  but  in  place  of  it  there 
is  a  swinging  tool  post  slide  whose  rear  end  is  journaled  upon  a 
lead  screw  which  gives  a  longitudinal  feed  when  the  slide  is  brought 
over  to  the  front  by  means  of  a  handle  for  that  purpose.  With  this 
driver,  straight  turning,  facing,  and  thread  cutting  is  quickly  and 
conveniently  done.  There  is  also  a  hand-rest  and  sometimes  a 
cutting-slide  or  cross-slide.  The  tail  spindle  has  a  long  run  and 
is  sometimes  worked  with  a  lever,  particularly  when  chucking 
work  is  to  be  done.  Occasionally  the  tail-stock  is  replaced  by  a 
turret  carrying  a  variety  of  tools  such  as  are  convenient  for  the 


FIG.  20.  —  A  "Fox"  Brass  Finishing  Lathe. 

brass  finisher.  These  lathes  are  usually  made  without  back  gears. 
They  are  run  at  very  high  speeds  and  in  the  hands  of  an  expert 
brass  finisher  do  the  work  very  rapidly,  both  as  to  turning  and 
boring  or  inside  finishing,  while  they  cut  threads  very  rapidly  by 
means  of  "  chasers." 

Forge  lathes  are  a  very  heavy  design  of  the  plain  engine  lathe, 
without  thread-cutting  mechanism  (although  some  manufacturers 
add  this  feature  so  as, to  make  the  lathes  available  as  a  complete 
engine  lathe  for  much  work  that  cannot  be  classed  as  forge  work). 
The  purpose  of  these  lathes  is  to  rough  down  large  forgings,  the 
users  claiming  that  it  is  more  economical  to  thus  bring  the  work 
to  the  " forging  sizes"  than  to  do  so  by  the  process  of  hammer- 


CLASSIFICATION   OF  LATHES 


57 


ing,  and  that  all  the  chips  thus  removed  may  be  worked  into 
other  forgings  by  which  this  waste  is  economically  recovered.  It 
is  therefore  their  practice  to  forge  the  work  (cylindrical  work, 
of  course)  to  dimensions  much  over  the  forge  sizes,  and  by  the  use 
of  the  heavy  forge  lathe  to  finish  them  to  customers  "  rough 
turned"  to  within  reasonable  limits  of  " finish  sizes." 

By  the  term  "  roughing  lathe  "  we  understand  that  the  design 
is  heavy  and  massive  with  a  very  powerful  driving  mechanism, 
lateral  and  cross  feeds  and  a  very  rigid  tool  holding  device.  Such 
a  lathe  is  seen  in  Fig.  21.  While  it  is  somewhat  analogous  to  the 


FIG.  21.  —  A  Roughing  Lathe. 

forge  lathe  it  is  usually  understood  to  be  of  much  less  capacity. 
And  while  the  forge  lathe,  being  for  handling  forgings  almost  ex- 
clusively, holds  the  work  on  centers,  the  roughing  lathe  should 
be  made  with  a  large  hole  in  the  spindle  so  that  work  may  be 
"roughed  out"  from  the  bar  as  well  as  when  held  on  centers,  or 
with  one  end  in  a  chuck  and  the  other  on  a  center.  And  here  it 
encroaches  upon  what  may  be  considered  the  field  of  the  so-called 
"  rapid  reduction  lathe  " ;  with  this  difference,  however,  that  in  the 
former  lathe  the  work  is  simply  roughed  out,  while  in  the  latter 
it  is  supposed  to  be  not  only  roughed  out  or  rapidly  reduced  to  near 
finished  sizes,  but  in  many  cases  entirely  finished,  or  finished  to 
dimensions  suitable  for  being  finished  by  grinding. 

In  the  third  class  we  commence  with  the  complete  engine  lathe, 
with  thread-cutting  mechanism,  back  geared  or  triple  geared,  with 


58  -MODERN   LATHE   PRACTICE 

a  compound  rest  which  in  the  larger  sizes  is  capable  of  power  feed 
at  all  angles.  Such  a  lathe  should  also  be  supplied,  especially 
in  the  larger  sizes,  with  a  tool-rest  to  attach  to  the  front  wing  of  the 
carriage  on  the  left-hand  side  for  turning  the  full  swing  of  the  lathe. 
The  larger  lathes,  particularly  those  that  are  triple  geared,  should 
have  a  tail-stock  arranged  with  two  sets  of  holding-down  bolts,  by 
means  of  which  one  set  may  be  loosened  and  the  tail-stock  set  over 
for  turning  tapers  without  removing  the  work  from  the  lathe,  as 
the  other  set  of  bolts  still  holds  the  tail-stock  to  its  place  on  the 
bed.  There  should  also  be  a  tail-stock  moving  device  consisting 
of  a  rack  attached  to  the  bed,  with  which  is  engaged  a 'pinion 
fixed  to  a  shaft  journaled  in  a  bracket  attached  to  the  tail-stock 
base.  By  means  of  a  crank  on  this  shaft  the  tail-stock  can  be 
easily  moved  to  any  desired  point  upon  the  bed. 

In  lathes  of  42-inch  swing  and  larger,  this  arrangement  should 
be  back-geared  by  the  introduction  of  a  second  shaft,  the  gears  be- 
ing in  ratio  of  2  to  1.  In  lathes  of  60-inch  swing  and  larger  this 
ratio  should  be  3  to  1.  The  tail-spindle  in  the  smaller  lathes  has 
the  usual  screw  and  hand  wheel  for  moving  it  back  and  forth.  In 
large  lathes  this  is  inconvenient  and  laborious.  The  hand  wheel 
should  be  placed  in  front  of  the  tail-stock  and  near  the  center,  being 
mounted  upon  a  short  shaft  at  right  angles  to  the  spindle  and 
journaled  in  a  bracket  fixed  to  the  tail-stock.  Upon  this  short 
shaft  is  also  a  miter  gear  engaging  with  another  fixed  to  a  shaft 
parallel  to  the  spindle  and  extending  to  the  rear  end  of  the  tail- 
stock  where  it  passes  through  another  bracket  and  has  fixed  upon 
it  a  spur  pinion  which  engages  a  spur  gear  fixed  to  the  tail-spindle 
screw,  and  by  which  mechanism  it  is  operated.  The  ratio  of  this 
spur  gear  and  pinion  is  usually  2  to  1  on  lathes  of  42-inch  swing,  and 
proportionately  more  on  larger  lathes.  By  the  use  of  this  mechan- 
ism the  operator  may  stand  opposite  the  tail  center  in  adjusting  his 
work  and  easily  reach  the  hand  wheel  controlling  the  movement  of 
the  spindle,  which  would  otherwise  require  an  assistant  to  operate. 

In  the  triple-geared  head-stocks  of  this  class  of  lathes  it  is  cus- 
tomary to  attach  the  face-plate  to  the  main  spindle  by  a  force-fit 
and  key  instead  of  making  it  readily  removable  by  a  coarse  thread, 
for  the  reason  that  it  is  to  be  driven  by  means  of  a  very  large 
internal  gear  bolted  to  its  rear  side  and  engaged  by  a  pinion  fixed 


CLASSIFICATION   OF   LATHES  59 

to  a  shaft  driven  by  the  cone  through  a  suitable  system  of  triple 
back  gearing.  In  this  case  the  cone  is  not  placed  upon  the  main 
spindle,  but  upon  a  separate  shaft  placed  sometimes  in  front  and 
sometimes  in  the  rear  of  it.  The  front  position  is  the  more  con- 
venient for  the  operator  in  making  the  necessary  changes  of  speed. 

It  is  upon  this  class  of  lathes  that  many  improvements  have 
been  made  in  the  last  few  years  in  the  thread-cutting  devices,  the 
original  idea  having  been  to  avoid  removing  and  replacing  "  change- 
gears"  when  threads  of  different  pitches  were  required  to  be  cut. 
The  first  attempt  in  this  line,  so  far  as  the  patenting  of  a  device 
shows,  was  made  by  Edward  Bancroft  and  William  Sellers  in 
1854,  and  taken  up  by  various  inventors  with  more  or  less  success 
but  never  brought  prominently  into  the  market  until  the  patent 
was  granted  to  Wendel  P.  Norton  in  1892,  when  somewhat  later 
on  the  mechanism  was  adopted  by  the  Hendey  Machine  Company, 
since  which  time  it  has  been  manufactured  with  much  success. 
In  the  meantime  many  other  devices  for  the  same  purpose  have 
been  devised  and  built,  so  that  now  every  tool  room  and  nearly 
every  machine  shop  making  any  pretense  to  modern  equipment 
possesses  lathes  having  some  one  of  these  "  rapid  change  gear  attach- 
ments "  included  in  their  design  or  arranged  to  be  attached  when 
desired  by  the  customer. 

In  the  development  of  the  engine  lathe  proper,  much  attention 
has  been  paid  to  the  supports  for  the  bed,  and  instead  of  the  former 
pattern  of  light  and,  later  on,  heavy  legs,  substantial  cabinets  of 
liberal  dimensions  and  weight,  have  been  designed  and  are  now 
used  upon  nearly  all  such  lathes,  the  only  exceptions  seeming  to 
be  upon  those  where  the  selling  price  renders  economy  in  the  use 
of  cast  iron  essential;  upon  lathes  too  small  and  light  to  justify 
their  use;  and  upon  lathes  built  by  the  more  conservative  manu- 
facturers who  have  not  yet  come  to  consider  this  class  of  improve- 
ments as  necessary  to  the  efficiency  of  their  machines. 

A  precision  lathe  is  designed  to  be  a  lathe  in  which  fineness  and 
exactness  in  all  its  parts  is  the  prime  consideration  rather  than  a 
great  range  of  work  or  capacity,  or  from  which  a  large  output  may 
be  realized.  It  is  therefore  not  necessary  that  it  should  be  very 
heavy  or  massive  except  in  so  far  as  its  weight  may  render  it  capa- 
ble of  greater  precision.  While  the  entire  design  and  construction 


60 


MODERN   LATHE   PRACTICE 


of  the  lathe  is  as  exact  as  possible,  the  effort  is  also  made  to  provide 
against  all  conditions  and  causes  that  shall  be  detrimental  to  its 
one  object,  that  of  turning  out  its  work  in  as  perfect  a  manner 
as  possible. 

These  being  the  conditions  under  which  it  is  designed  and  built, 
it  is  an  expensive  lathe,  as  the  most  skilful  labor  is  used  in  its  con- 
struction and  the  time  devoted  to  this  work  is  always  liberal. 
It  is,  therefore,  essentially  a  lathe  for  the  tool  room  and  the  labora- 
tory rather  than  the  manufacturing  department,  and  with  it 
master  screws  of  very  great  exactness  and  all  similar  work  is  per- 
formed. It  is,  of  course,  an  engine  lathe  in  its  general  design, 


FIG.  22.  —  A  Rapid  Reduction  Lathe. 

although  there  are  more  or  less  changes  of  form  and  manner  of 
assembling  the  parts  introduced  for  the  purpose  of  avoiding  the 
effects  of  strains,  protecting  bearings  from  dirt,  insuring  accuracy 
of  movement  of  the  several  parts,  and  so  on,  everything  in  the 
design  and  construction  being  subordinated  to  the  one  condition 
of  the  greatest  precision  and  accuracy,  not  only  in  the  entire 
machine  but  in  all  its  individual  parts. 

The  rapid-reduction  lathe,  shown  in  Fig.  22,  is  another  form  of 
a  complete  engine  lathe,  built  heavy  and  strong,  with  a  powerful 
and  somewhat  complicated  driving  mechanism  and  very  strong 
feed.  The  tool  holding  device  should  accommodate  at  least  two 
tools  and  hold  them  very  rigidly.  It  should  have  thread-cutting 


CLASSIFICATION  OF  LATHES 


61 


facilities  so  that  pieces  requiring  threads  may  be  entirely  finished 
in  this  respect.  It  should  be  an  accurately  working  machine  so 
that  it  may  not  only  rapidly  reduce  the  stock  to  near  the  finishing 
dimensions,  but  finish  all  ordinary  work  to  the  given  sizes,  or  to 
such  dimensions  as  may  be  called  for  when  the  piece  is  to  be  finished 
by  grinding.  Such  a  lathe  may  be  arranged  with  a  series  of  stops 
both  for  diameters  and  lengths  and  thus  do  much  of  the  work  done 
in  a  very  much  more  expensive  turret  lathe.  It  will  be  of  much 
convenience  to  have  a  hollow  spindle,  bored  out  as  large  as  pos- 
sible so  as  to  admit  of  running  a  bar  of  round  stock  through  it, 
holding  it  in  a  chuck  and  forming  one  end  of  the  pieces,  then  cutting 
them  off,  leaving  the  remainder  of  the  work  on  the  opposite  end 


FIG.  23.  —  A  Gap  Lathe. 


of  the  piece  to  be  done  at  a  second  operation  in  this  lathe  or  some 
similar  machine.  In  working  up  round  stock  in  this  manner  the 
lathe  should  be  provided  with  a  cutting-off  slide  constructed 
similar  to  that  on  a  turret  lathe. 

A  gap  lathe,  shown  in  Fig.  23,  is  one  in  which  the  top  of  the 
bed  is  cut  away  for  a  space  immediately  in  front  of  the  face-plate 
for  the  purpose  of  increasing  the  swing  of  the  lathe  so  that  much 
larger  work  may  be  turned  or  bored,  either  when  held  upon  centers 
or  in  a  chuck.  This  type  of  lathe  is  more  in  favor  in  English 
machine  shops  than  those  of  this  country,  where  the  gap  lathe  is 
seldom  seen.  When  the  work  of  the  lathe  is  not  of  such  a  nature 
as  to  require  the  gap,  it  is  usually  closed  up  in  one  of  two  ways. 
The  first  method  is  to  have  a  portion  of  bed  exactly  like  the  main 
part  and  of  such  a  length  that  it  will  exactly  fit  in  the  space  form- 


62  MODERN   LATHE   PRACTICE 

ing  the  "gap."  The  other  method  is  to  have  that  portion  of  the 
bed  upon  which  the  head-stock  is  attached,  of  the  full  height,  while 
the  remainder  of  the  bed  is  lowered  sufficiently  to  furnish  a  support 
for  a  sliding  supplemental  bed  whose  depth  is  equal  to  the  depth 
of  the  gap.  This  supplemental  bed  when  closed  up  to  the  face  of 
the  head-stock  completes  the  bed  by  filling  the  entire  cut-away 
portion  completely  to  the  rear  end.  When  it  is  desired  to  form  a 
/'gap"  this  supplemental  bed  is  moved,  toward  the  rear  end  of  the 
bed  proper  to  any  desired  distance  to  leave  the  required  space  or 
gap  for  the  work  in  hand,  and  secured  by  bolts  arranged  for  that 
purpose.  In  a  large  machine  shop,  with  the  proper  lathes  for 
handling  whatever  work  the  shop  is  called  upon  to  do,  the  gap  lathe 
is  not  usually  necessary  and  will  seldom  be  found,  but  in  jobbing 
shops,  particularly  those  with  a  modest  equipment  of  tools,  the 
gap  lathe  may  often  be  found  convenient  for  doing  exceptionally 
large  jobs  such  as  pulleys,  balance-wheels  and  the  like,  as  these 
jobs  may  come  along  so  seldom  that  it  would  not  be  advisable  to 
incur  the  expense  of  a  lathe  large  enough  to  swing  them,  and  which 
would  be  liable  to  be  idle  a  large  portion  of  the  time. 

The  gap  lathe  is  provided  with  the  usual  thread-cutting 
mechanism  and  is  in  all  respects  a  complete  engine  lathe.  It  is 
not  usually  as  rigid  as  a  solid  bed  lathe  and  therefore  not  as  effi- 
cient in  taking  heavy  cuts. 

The  fourth  class,  including  the  various  types  of  special  lathes, 
would  of  necessity  be  a  very  large  one  if  an  attempt  were  made 
to  enumerate  them  all,  and  the  list  might  prove  tiresome  to  the 
busy  reader.  Those  introduced  in  the  foregoing  list  are  of  the 
well-known  and  recognized  types  and  seem  to  be  sufficient  for 
the  purposes  of  this  work. 

Forming  lathes  are  of  heavy  and  massive  design  and  construc- 
tion, and  provided  with  powerful  driving  mechanism,  adapted 
to  rather  slow  speeds,  and  with  fine  feeds,  owing  to  the  large  extent 
of  the  cutting  surface  of  the  tools  used  in  them.  These  tools 
require  special  forms  of  rest  for  supporting  them  which  are  of 
strong  but  simple  design,  as  many  of  the  forming  tools  are  simply 
flat  steel  plates  with  the  form  to  be  turned  cut  in  the  edge,  so 
that  when  dull  they  may  be  sharpened  by  grinding  the  top  face 
and  not  changing  the  form.  Forming  lathes  should  have  hollow 


CLASSIFICATION   OF   LATHES  63 

spindles,  bored  out  much  larger  in  proportion  than  in  other  types 
of  lathes.  The  author  has  designed  and  built  these  lathes  of 
28-inch  swing  with  a  spindle  7J  inches  in  diameter  and  bored  out 
to  5J  inches,  so  as  to  take  in  a  bar  of  5-inch  steel.  As  this  size 
weighs  about  85  pounds  to  the  foot,  or  a  bar  16  feet  long  weighs 
over  1 ,300  pounds,  it  will  be  seen  that  ample  provision  was  needed 
for  the  weight  to  be  borne  upon  the  main  spindle  bearings  in  ad- 
dition to  the  weight  of  the  lathe  parts,  and  that  while  the  driving 
power  necessary  for  operating  with  a  wide  forming  tool  on  steel  of  5 
inches  diameter  was  a  serious  matter,  that  of  providing  for  the 
rotating  of  this  unusual  load  was  a  considerable  addition  to  it. 
However,  they  met  the  required  conditions  and  succeeded  in 
turning  out  much  work  even  of  this  comparatively  large  diameter. 

Naturally  the  forming  lathe  requires  no  provision  for  thread 
cutting,  but  a  geared  feed  should  be  used  and  will  need  to  be  of 
ample  power  to  withstand  the  very  severe  strain  to  which  it  will 
be  put. 

Pulley  lathes,  as  they  are  commonly  termed,  might  more 
appropriately  be  called  pulley-turning  machines,  or  even  pulley- 
making  machines,  since  some  of  them  make  the  pulley  complete, 
with  the  exception  of  splining  and  drilling  and  tapping  for  the  set- 
screws.  In  some  of  these  machines  the  boring  is  going  on  and  the 
reaming  is  also  done  while  the  turning  is  taking  place.  In  other 
forms,  one  machine  does  the  boring  and  reaming,  which  may  be  done 
at  quite  high  relative  speed,  while  the  turning  must  be  compara- 
tively slower  and  is  done  in  another  machine.  Thus  one  machine  for 
boring  and  reaming  may  furnish  work  enough  for  several  turning 
machines. 

In  the  pulley-turning  lathes  there  must  be  a  strong  driv- 
ing mechanism  since  comparatively  large  diameters  are  turned, 
although  even  the  roughing  cut  is  light  when  compared  with  that 
frequently  taken  by  other  lathes.  Two  and  sometimes  more 
tools  are  used,  being  located  both  at  the  front  and  back  of  the  bed, 
(those  at  the  back  being  bottom  side  up).  In  some  machines  the 
tools  commence  the  operation  in  the  center  of  the  face  of  the  pulley, 
and  each  tool  or  pair  of  tools  (one  roughing  and  one  finishing), 
are  fed  away  from  the  center,  and  with  the  slide  upon  which  the 
tool  block  travels  set  in  a  slightly  inclined  position  with  reference 


64  MODERN   LATHE   PRACTICE 

to  the  axis  of  the  lathe  so  as  to  produce  the  properly  "  crowned 
face"  of  the  pulley.  With  four  tools  thus  arranged,  the  pulley 
is  completely  turned  during  the  time  necessary  for  a  tool  to  travel 
across  one  half  of  the  face  of  the  pulley  plus  the  distance  apart 
of  the  roughing  and  the  finishing  tool,  say  from  an  inch  to  an  inch 
and  a  half. 

When  the  pulley-turning  lathe  is  arranged  for  turning  cone 
pulleys  it  is  customary  to  have  as  many  tools  as  there  are  steps 
to  the  cone  pulley,  each  held  in  a  separate  tool  post  fixed  in  a  single 
tool  block  having  a  lateral  power  feed  and  a  transverse  adjustment 
for  setting  to  the  proper  diameter.  The  tool  posts  set  in  T-slots 
and  the  tools  are  set  with  relation  to  each  other  so  as  to  turn  the 
proper  relative  diameters  of  the  several  steps.  The  tool  block  and 
the  slide  upon  which  it  runs  is  adjustable  to  the  right  inclination 
or  "taper"  to  properly  crown  all  the  steps  of  the  cone  at  once, 
and  when  the  tools  have  passed  over  one  half  the  face  of  the  steps, 
this  block  and  slide  may  be  shifted  and  properly  adjusted  to  turr 
the  other  half  of  each  step.  In  this  form  of  pulley  turning  it  is 
usual  to  make  two  cuts,  a  roughing  and  a  finishing  cut,  and  when 
turning  up  to  the  face  of  the  different  steps  to  draw  back  the  entire 
number  of  tools  by  means  of  the  transverse  slide  which  may  be 
fed  back  by  hand  for  that  purpose. 

Pulley-turning  and  boring  lathes  or  machines  are  built  very 
broad  as  compared  with  an  engine  lathe  and  with  very  short  beds, 
as  the  width  of  a  pulley  face,  or  the  combined  faces  of  the  several 
steps  of  a  cone  pulley,  is  the  extent  of  their  lateral  feed  in  any  case. 

The  boring  and  reaming  mechanism  should  have  a  power  feed 
so  as  not  to  require  the  constant  attendance  of  the  operator,  who 
may  easily  run  one  boring  and  reaming  machine  and  two  surface 
turning  machines. 

Shafting  lathes  or  shaft-turning  lathes  may  be  arranged  from 
any  good  engine  lathe  provided  the  bed  is  long  enough  for  the 
purpose,  by  adding  to  it  a  three-tool  shafting  rest  and  a  shaft 
straightener.  Still  a  lathe  that  is  especially  designed  as  a  shaft- 
turning  lathe  will  be  better  adapted  for  the  purpose  and  will  turn 
out  more  good  shafting  with  the  same  expenditure  of  capital  and 
labor  than  the  engine  lathe  arranged  with  attachments  for  the 
purpose.  In  the  properly  designed  shaft- turning  lathe  there  is  a 


CLASSIFICATION   OF  LATHES  65 

heavy  shaft  running  the  length  of  the  lathe  bed  and  arranged  to 
communicate  power  to  a  face  gear  and  driver  journaled  on  the 
front  end  of  the  tail-stock,  by  means  of  which  the  shaft  to  be 
turned  may  be  driven  from  this  end  as  well  as  from  the  head-stock 
end.  This  is  very  useful  in  turning  long  shafts  in  which  the  tor- 
sional  strain  would  be  great,  as  the  power  may  be  applied  at  the 
tail-stock  to  turn  one  half  of  the  shaft  and  then  applied  direct  from 
the  head-stock,  or  it  may  be  applied  at  both  ends  continuously  and 
simultaneously. 

There  should  be  a  force  pump  to  keep  the  cutting-tools  constantly 
supplied  with  a  stream  of  whatever  lubricant  is  being  used.  This 
pump  may  be  driven  from  the  shaft  above  mentioned,  which  is 
located  at  the  center  of  the  bed  and  below  the  bridge  of  the  car- 
riage. The  three-tool  rest  carries  its  own  center  rest,  but  it  is 
customary  to  support  the  shaft  being  turned  by  easily  removable 
rests  used  between  the  carriage  and  the  head-stock  or  tail-stock, 
as  the  operator  finds  necessary.  These  are  generally  composed 
of  two  wooden  blocks  resting  on  the  V's  of  the  lathe  and  somewhat 
lower  than  the  lathe  centers.  The  upper  block  has  a  V-shaped 
groove  for  the  shaft  to  rest  in  and  is  raised  up  and  held  in  place  by 
a  wooden  wedge  inserted  just  far  enough  to  give  proper  support 
to  the  shaft  so  as  not  to  permit  it  to  sag  during  the  process  of  turn- 
ing. There  are  three  turning  tools  usually  employed.  The  first 
is  a  roughing  tool;  the  second  cuts  the  shaft  very  closely  to  size, 
while  the  third  takes  an  extremely  light  cut,  completing  the 
work,  so  that  by  running  once  over  the  shaft  from  end  to  end  it  is 
completely  finished.  Two  tools  are  placed  at  the  left  of  the  center 
rest  fixed  to  the  tool  block,  and  one,  the  final  finishing  tool,  at  the 
right.  As  these  three  tools  and  the  center  rest  occupy  considerable 
length  upon  the  shaft  the  lathe  is  provided  with  extra  long  centers 
so  as  to  reach  the  work.  The  center  rest  is  provided  with  split 
collars  bored  to  the  size  that  the  second  tool  leaves  the  shaft. 

The  turret  lathe,  shown  in  Fig.  24,  now  so  well  and  favorably 
known,  is  a  comparatively  recent  invention  and  doubtless  origi- 
nated in  the  use  of  a  multiple  tail-stock  which  was  formerly  used  on 
small  work  where  more  than  one  tool  was  desirable.  Our  English 
friends  recognize  its  value  and  usefulness,  and  one  author  speaks 
of  it  as  "the  common  capstan  tool-rest."  In  this  country  much 


66 


MODERN   LATHE   PRACTICE 


has  been  done  to  develop  and  bring  into  popular  form  the  turret 
lathe  by  such  builders  as  Jones  &  Lamson,  Warner  &  Swasey, 
Potter  &  Johnson,  Bullard  and  others. 

While  the  turret  lathe  in  its  perfected  form  is  now  a  complete 
machine,  the  turret  idea  was  first  applied  to  engine  lathes,  and  turret 
attachments  are  so  universally  popular  that  most  of  the  lathe 
manufacturers  now  make  them  of  dimensions  suitable  for  their 
lathes,  and  attach  them  either  to  the  lathe  carriage  or  to  a  special 
bed  which  may  be  fastened  to  the  lathe  bed  upon  the  removal 


FIG.  24.  —  A  Turret  Lathe. 

of  the  tail-stock.  A  great  variety  of  work  may  be  done  in  the 
turret  lathe,  its  principal  rival  being  the  automatic  screw  machine, 
whose  economy  lies  principally  in  the  fact  that  one  operator  may 
take  care  of  a  number  of  machines,  each  of  these  machines  depend- 
ing principally  for  their  success  upon  the  turret  with  its  multiplicity 
of  tools.  And  this  idea  of  a  turret  carrying  from  four  to  eight  tools 
is  applied  in  a  great  variety  of  ways  and  to  a  large  variety  of 
machines  on  account  of  the  ease  with  which  any  desired  tool  may 
be  brought  into  a  working  position. 

The  head-stock  of  a  turret  lathe  is  made  in  several  ways,  from 
that  of  a  plain  head  without  back  gears  to  one  with  a  large  variety 
of  speeds,  controlled  by  handles  operating  clutches,  or  friction 
driving  devices,  or  both,  and  which  may  be  operated  while  the 
machine  is  in  motion.  In  some  cases  the  head-stock  is  cast  in  one 
piece  with  the  bed,  in  others  fitted  to  it  in  a  similar  manner  to  that 
of  an  ordinary  lathe.  In  still  others  the  head  has  a  transverse 
movement  on  the  bed  upon  which  it  slides  and  its  movement  is 
easily  controlled  by  the  operator. 


CLASSIFICATION   OF  LATHES  67 

The  turret  is  designed  and  constructed  in  a  variety  of  forms, 
but  principally  either  circular  or  hexagonal.  It  is  mounted  usually 
in  a  horizontal  position,  that  is  with  its  axis  vertical,  but  still  in 
some  of  the  best  machines,  notably  the  Gisholt,  it  is  pivoted  in  an 
inclined  position,  the  object  being  to  bring  the  long  tools,  made 
necessary  by  a  large  machine,  up  out  of  the  way  of  the  operator  as 
they  swing  over  the  front  of  the  machine. 

In  the  smaller  hand  machines  and  in  many  of  the  turrets  fur- 
nished upon  ordinary  engine  lathes  the  turrets  are  rotated  by  hand 
as  each  change  is  required,  but  in  the  larger  and  more  complete 
machines  the  sliding  movement  of  the  turret  effects  its  rotation 
at  the  proper  time  near  its  extreme  rear  position. 

There 'is  no  carriage,  properly  so  called,  upon  a  regular  turret 
lathe.  A  cutting-off  slide  carrying  two  tool-posts,  one  in  front 
and  one  in  the  rear,  serve  to  carry  a  cutting-off  tool  and  a  facing 
tool,  or  one  for  doing  forming  within  certain  limits.  The  spindle 
being  hollow,  and  a  large  part  of  the  work  of  the  turret  lathe 
adapted  for  steel  work  being  made  direct  from  the  bar,  these  tools 
are  very  useful. 

Some  turret  lathes  are  particularly  adapted  for  a  large  variety 
of  chucking  and  forming  work,  which  they  perform  very  accurately 
and  economically,  an  elaborate  system  of  stops  for  the  turret  slide 
rendering  them  very  efficient  for  this  work. 

The  tools  that  may  be  used  in  a  turret  are  almost  without  num- 
ber, and  the  expert  operator  readily  attacks  the  most  complicated 
pieces  and  brings  them  out  with  excellent  finish  and  with  surprising 
accuracy.  Internal  and  external  threads  are  readily  cut  very  true 
to  size  and  with  rapidity. 

The  screw  machine  is  very  closely  allied  to  the  turret  lathe, 
so  called,  and  the  smaller  sizes  are  fitted  with  what  is  called  a  "wire 
feed,"  which  will  automatically  feed  in  the  bar  against  the  turret 
stop  as  soon  as  it  is  released  by  opening  the  chuck.  This  is  in  the 
hand  screw  machine.  In  the  automatic  screw  machine  all  these 
movements  are  made  automatically  when  once  the  machine  is  set 
up,  the  tools  properly  adjusted,  the  bar  of  stock  once  introduced 
and  the  machine  started,  and,  barring  accidents,  the  machine  con- 
tinues to  run,  dropping  its  work  into  a  pan  as  it  is  completed  and 
cut  off,  until  the  bar  of  stock  is  almost  entirely  used  up. 


68  MODERN   LATHE  PRACTICE 

Multiple  spindle  lathes  are  usually  those  having  two  spindles. 
These  may  be  side  by  side  for  the  purpose  of  performing  two  similar 
operations  simultaneously;  or  one  spindle  may  be  considerably 
higher  than  the  other,  above  the  bed,  thus  giving  two  different  capac- 
ities as  to  the  diameter  of  work  that  can  be  accommodated  on 
the  same  lathe ;  the  larger  swing  being  frequently  used  for  boring 
or  similar  work.  Notably  of  this  type  of  lathe  is  that  put  in  the 
market  by  J.  J.  McCabe. 

While  the  general  and  well-marked  types  of  lathes  have  been 
specified  in  this  classification  it  must  not  be  understood  that  the 
list  is  complete,  as  there  are  many  special  lathes,  each  of  excellent 
mechanism  and  well  adapted  to  the  special  work  for  which  it  is 
designed,  that  do  not  appear  here,  and  that  it  is  manifestly  impos- 
sible to  classify  and  describe  in  detail.  Frequently  they  may  be 
assigned  to  some  one  of  the  classes  or  sub-divisions  here  set  forth, 
as  all  lathes  must  partake  in  some  respect  of  the  essential  parts  of 
those  described. 

Further  on  in  this  work  many  practical  examples  of  the  lathes 
described  in  this  chapter  will  be  found,  their  builders'  names  being 
given  and  their  particular  features  pointed  out  and  commented 
upon,  and  to  them  the  reader  is  referred  for  the  better  examples  of 
each  of  the  classes  enumerated  in  this  chapter. 


CHAPTER  IV 
LATHE  DESIGN:  THE  BED  AND  ITS  SUPPORTS 

The  designer  of  lathes.  The  manufacturer's  view  of  a  lathe.  The  proper 
medium.  Cause  of  failure.  The  visionary  designer.  Conscientious 
efforts  to  improve  in  design.  Design  of  the  lathe  bed.  Elementary 
design.  Professor  Sweet's  observations.  The  parabolic  form  of  lathe 
beds.  The  author's  design.  Form  of  the  tracks.  Bed  of  the  old  chain 
lathe.  The  English  method  of  stating  lathe  capacity.  Method  of 
increasing  the  swing  of  the  lathe.  The  Lodge  &  Shipley  lathe  bed. 
Uniform  thickness  of  metal  in  beds.  Ideal  form  of  bed.  Cross-ties,  or 
bars.  Four  Vs.  Flat  surfaces.  Lathe  bed  supports.  Height  of  lathe 
centers.  Wooden  legs  for  lathe  beds.  An  early  form  of  braced,  cast 
iron  legs.  Cabinets  or  cupboard  bases.  Old  style  cast  iron  legs  still 
in  use.  Form  of  cabinets.  Principles  of  the  design  of  cabinets.  Cabi- 
nets for  small  lathes.  The  Lodge  &  Shipley  cabinet.  The  Hendey- 
Norton  cabinet. 

To  the  experienced  and  conscientious  designer  of  machine  tools 
the  condition  is  frequently  forced  upon  him  that  it  is  often  easier, 
and  usually  far  more  agreeable,  to  design  machines  as  he  really 
believes  they  should  be,  than  to  design  such  machines  as  will  meet 
the  popular  requirements  of  the  market.  He  may  be  sure  that  a 
certain  plan  would  make  really  a  better  and  more  efficient  machine, 
yet  he  must,  from  the  outset,  consider  the  kind  of  a  machine  the 
customers  want  and  will  buy  and  pay  for,  since  they  are,  as  has  been 
often  said,  "the  court  of  final  resort"  in  the  matter,  and  machine- 
tool  builders  manufacture  machines  to  sell,  and  not  for  the  pur- 
pose of  exploiting  individual  opinions,  however  good  they  may  be, 
or  the  fads  and  fancies  of  draftsmen  who  are  sometimes  imbued 
with  visionary  and  impractical  ideas. 

The  manufacturer  himself  may  be  perfectly  sure  that  the  ma- 
chines he  is  turning  out  are  not  the  best  adapted  for  the  purposes 
for  which  they  are  used,  or  the  best  he  could  build  for  the  money. 

69 


70  MODERN   LATHE   PRACTICE 

He  may  so  far  have  the  courage  of  his  convictions  as  to  build  for 
his  own  use  machines  quite  different  from  those  he  manufactures 
for  his  customers.  Yet  for  sale  he  must  build  what  his  customers 
want  with  small  regard  for  his  own  personal  opinions. 

By  this  it  is  not  meant  that  the  builder  does  not  use  his  judg- 
ment in  a  mechanical  way,  or  that  he  does  not  endeavor  to  build  the 
best  machines  possible,  inasmuch  as  he  does  give  this  very  question 
much  time,  attention,  and  study.  Yet  he  must,  from  the  very 
nature  of  the  case,  always  keep  in  mind  the  question,  "What  will 
the  customers  think  of  this  new  machine?  "  "  Will  this  device  be 
a  success,  or  will  it  prove  a  failure?"  Some  machines  that  have 
been  put  on  the  market  with  feelings  of  much  trepidation  have 
proven  great  money-makers,  while  other  machines  possessing  much 
mechanical  excellence  have  fallen  flat  and  a  large  majority  of  the 
customers  refused  to  endorse  them.  The  author  has  seen  many 
such  cases,  and  this  has  probably  been  the  experience  of  every  man 
who  has  designed  and  built  machine  tools. 

The  proper  medium  in  the  matter  seems  to  be  to  keep  as  closely 
in  touch  as  possible  with  the  purchasers  of  machinery;  to  ascer- 
tain their  needs  and  preferences  as  closely  as  may  be;  to  anticipate 
their  wants  when  possible,  but  at  the  same  time  with  conservatism; 
and  to  avoid  putting  entirely  new  devices  on  the  market  until 
they  have  been  thoroughly  tested  in  the  home  shop  and  by  a  few 
friendly  shops  outside  of  it.  And  by  entirely  new  devices  is  meant 
substantially  new  and  complete  machines,  as  the  builder  will  fre- 
quently have  parts  of,  or  attachments  to,  the  regular  line  of  ma- 
chines that  are  made  to  the  order  of  a  particular  customer  and  that 
he  feels  perfectly  sure  of  being  well  suited  to  the  work  that  it 
is  expected  to  perform;  yet  in  these  cases  considerable  caution  is 
necessary. 

The  one  fruitful  source  of  difficulty,  disappointment,  and  failure 
to  be  most  avoided  in  the  production  of  new  devices  is  the  mania 
often  manifested  by  designers  to  produce  something  absolutely 
new,  decidedly  novel,  the  like  of  which  no  one  has  ever  seen  or 
dreamed  of,  and  that  will  startle  the  mechanical  world,  revolu- 
tionize the  business,  and  prove  its  author  a  veritable  Napoleon  of 
mechanical  science. 

When  confronted  with  such  a  man  or  such  a  condition,  the 


LATHE  DESIGN:  THE  BED  AND   ITS  SUPPORTS         71 

wiser  course  will  be  to  abandon  such  ambitious  attempts  to 
eclipse  all  previous  efforts,  get  down  out  of  the  clouds,  design 
something  of  practical  utility,  even  if  it  is  not  strikingly  new;  some- 
thing that  past  experience  gives  some  guarantee  of  success; 
something  that  will  surely  bring  the  proper  financial  return  and 
be  a  credit  to  the  shop.  It  is  always  well  to  remember,  when 
tempted  to  go  off  on  a  tangent  after  something  new  and  mar- 
velous, that  "a  good  adaptation  is  better  than  a  poor  original," 
and  that  when  Solomon  said  that  "  there  is  no  new  thing  under  the 
sun,"  he  did  not  come  far  from  the  truth,  since  many  of  the  things 
we  think  are  new  may  be  found  in  almost  the  identical  form,  that 
have  been  invented,  used,  and  discarded  years  ago,  as  the  records 
of  many  mechanical  libraries  as  well  as  the  United  States  [Patent 
Office  will  furnish  abundant  evidence. 

By  the  foregoing  remarks  it  is  not  intended  to  discourage 
originality,  original  thought  and  research,  or  the  proper  ambition 
to  improvement,  for  we  often  produce  more  of  real  value  by  the 
effort  to  evolve  mechanical  improvements  than  by  the  design  of 
entirely  new  machines,  and  the  studious  and  observing  designer 
will  always  be  on  the  alert  to  devise  improvements  upon  existing 
forms  and  processes. 

These  observations  and  suggestions  apply  with  as  much  force  in 
the  efforts  to  improve  the  lathe  as  any  other  machine  in  common 
use.  Being  the  oldest  machine  in  the  machine  shop  does  not  in 
any  respect  limit  the  field  for  improvements  in  it.  Neither  does 
it  preclude  the  design  of  entirely  new  machines  that  may  have, 
perhaps,  very  little  of  the  characteristics  of  a  lathe,  although  we 
must  necessarily  be  confined  to  the  essentials  heretofore  discussed, 
namely,  a  bed,  upon  which  rest  the  head-stock,  tail-stock,  and  car- 
riage, or  their  equivalents,  if  we  would  claim  that  our  machine  is  a 
lathe. 

With  these  preliminary  statements  relative  to  the  conditions 
and  requirements  of  good  and  successful  designing,  we  may  take 
up  the  designing  of  lathes  somewhat  in  detail  and  inquire  into  the 
design  of  the  individual  parts  and  groups  of  parts,  giving  some  of 
the  ideas  of  men  prominent  in  this  field,  and  adding  such  comments 
and  suggestions  as  seem  proper  and  pertinent  to  the  case  as  the 
matter  is  proceeded  with. 


72 


MODERN   LATHE  PRACTICE 


In  carrying  out  this  plan  it  will  be  natural  to  commence  with 
the  bed,  considering  its  use  and  purpose,  and  the  proper  form  to 
fulfil  the  requirements  of  this  particular  part. 

The  lathe  bed,  considered  in  an  elementary  way,  and  in  the 
case  of  a  lathe  of  moderate  length,  may  be  taken  as  a  beam,  sup- 
ported at  each  end  and  in  its  turn  supporting  at  one  end  the  head- 
stock,  at  the  other  end  the  tail-stock,  and  in  the  center  the  carriage, 
as  represented  in  Fig.  25. 


\ 


FIG.  25.  —  Elementary  Form  of  Lathe  Bed. 

This  being  the  problem,  and  as  the  head-stock  and  the  tail- 
stock  stand  directly  over  the  legs  or  supports,  we  might  consider 
the  problem  as  that  of  a  beam  loaded  at  the  center,  which  would 
naturally  suggest  that  the  under  side  of  the  bed  instead  of  being 
straight  should  be  a  parabolic  curve.  This  would  result  in  the 
form  shown  in  Fig.  26,  which  would,  if  the  carriage  was  stationary, 

l 


FIG.  26.  —  Parabolic  Form  of  Lathe  Bed. 

conform  to  the  conditions  of  the  problem.  But,  while  the  carriage 
is  not  stationary,  it  is  located  at  what  would  normally  be  the  weak- 
est point  along  the  length  of  the  bed,  namely,  a  point  farthest 
from  either  support.  So  far  the  parabolic  curve,  then,  is  correct. 
But  while  we  have  been  placing  our  supports  at  the  extreme 
end  of  the  bed  we  have  no  condition  of  the  case  which  makes  it 
incumbent  upon  us  to  do  so.  In  other  words,  we  may  add  a  por- 
tion to  each  end  of  the  bed,  outside  of,  or  beyond  the  line  of  these 
supports,  in  the  form  shown  in  Fig.  27,  showing  a  modified  form 


LATHE  DESIGN:  THE  BED   AND   ITS  SUPPORTS 


73 


of  the  lathe  bed,  the  extensions  at  each  end  being  in  the  form  of  a 
beam  supported  at  one  end.  Theoretically,  then,  this  would  seem 
to  be  the  proper  form  of  a  lathe  bed  in  order  that  it  might  conform 
to  the  necessary  requirements  as  to  form  and  its  ability  to  sustain 
the  usual  weights  and  strains  to  which  it  will  be  subjected,  and 
at  the  same  time  not  be  of  excessive  weight,  which  would  entail 
unnecessary  expense. 

This  is  substantially  the  view  taken  by  Prof.  John  E.  Sweet  in 
reference  to  machine  beds.  He  says: 

"No  reasoning  can  make  it  out  that  the  place  for  the  support 
of  an  ordinary  sized  lathe  bed  at  the  tail-stock  end  of  the  lathe  is  at 
the  end.  If  placed  a  considerable  distance  from  the  end,  and  the 
tail-stock  is  at  the  end,  it  is  better  supported  than  when  in  the 
middle  of  the  present  style  of  lathes  and  also  better  supported  at 


FIG.  27.  —  Modified  Parabolic  Form  of  Lathe  Bed. 

all  other  points.  At  the  head-stock  end  it  is  quite  a  different  matter 
as  the  head-stock  is  always  fixed  and  is  usually  heavier  loaded, 
exclusive  of  its  own  greater  weight.  Where  the  head-stock  end 
support  is  a  closet,  there  is  no  way  to  make  it  look  right  except  to 
have  the  closet  the  same  width  as  the  head-stock  is  long. 

"In  the  case  of  a  planing  machine  bed  up  to  12or  15  feet  in  length 
there  is  no  reason  for  having  three  pairs  of  supports.  Unless  the 
foundation  is  absolutely  unyielding  —  a  thing  that  is  more  rare 
than  the  other  kind  —  the  three  or  more  pairs  of  supports  are 
especially  bad,  and  to  attempt  to  hold  the  foundation  true  with  a 
frail  planer  bed  is  foolish.  The  distance  between  the  supports  in 
Fig.  28  is  no  greater  than  in  29,  and  as  in  no  case  would  the  center 
of  the  load  in  planing  overhang  the  supports  more  than  a  slight 
distance  the  style  shown  in  Fig.  28  is  quite  as  well  supported  as  the 
other;  and  when  the  iron  in  the  legs  and  the  work  to  fit  them  are 
taken  into  account,  if  they  were  all  put  into  the  casting  the  bed 


74 


MODERN   LATHE   PRACTICE 


could  be  brought  down  to  the  floor  as  in  Fig.  30,  greatly  improv- 
ing the  structure. 

"  Another  improvement  is  to  use  the  iron  usually  put  in  the  cross- 


FIG.  28. — Prof.  Sweet's  Form  of  Bed,  supported  at  Two  Points  only. 

girts  —  which  do  not  stiffen  the  bed  in  any  way  to  any  great  extent 
—  and  use  it  in  bottom  and  top  webs,  making  the  thing  a  f our- 


FIG.  29. — A  Common  Form  of  Lathe  Bed,  Supported  at  Three  Points. 

sided  box,  which  is  from  four  to  a  dozen  times  stiffer  in  all  direc- 
tions, and  then  rest  the  whole  thing  on  three  points,  one  under  the 


FIG.  30.  —  Prof.  Sweet's  Design  Applied  to  a  Planer  Bed. 

back  of  each  housing  and  one  under  the  middle  toward  the  other 
end.  The  whole  thing,  including  patterns  and  setting,  will  cost 
no  (or  very  little)  more  and  be  four  times  better  than  present 
practice. 


LATHE   DESIGN:  THE   BED   AND   ITS  SUPPORTS         75 

"If  the  bed  is  supported  at  the  same  points  when  it  is  planed 
and  fitted  up,  no  attention  or  skill  is  required  in  the  erection  — 
just  set  it  anywhere  and  on  anything  solid,  and  that  is  all  that  need 
be  or  can  be  done." 

There  is  "meat  for  reflection"  in  what  Professor  Sweet  says 
(as  there  usually  is),  and  the  principle  upon  which  he  makes  his 
deductions  is  undoubtedly  correct. 

To  render  the  comparison  more  apparent  and  in  a  practical 
manner  the  two  views  shown  in  Figs.  31  and  32  are  given.  In 


FIG.  31.  —  The  Parabolic  Design  of  a  Lathe  Bed. 

Fig.  31  the  parabolic  design  is  shown  in  proper  proportion  for 
supporting  the  head-stock,  tail-stock,  and  carriage,  and  the  propor- 
tions laid  out  are  ample  for  all  purposes,  as  is  also  the  supports 
and  their  distance  from  each  other.  In  Fig.  32  is  shown  a  rectangu- 
lar design  of  bed  of  like  length  and  of  sufficient  depth  to  give  the 
requisite  strength,  provided  there  is  a  central  support  added  to 
prevent  a  sinking  in  the  center  of  the  bed,  as  the  distance  between 
supports  would  otherwise  be  too  great.  While  nothing  has  been 
added  to  the  strength  or  the  stiffness  of  the  bed,  we  have  been 


FIG.  32.  —  The  Rectangular  Form  of  Equal  Strength. 

obliged  to  add  the  central  support  and  in  addition  to  this  the 
weight  of  the  parabolic  form  of  bed  is  1,390  pounds,  while  the  rect- 
angular form  is  1,550,  a  very  material  addition  without  compen- 
sating advantages;  and  at  the  same  time  we  have  the  disadvantage 
referred  to  by  Professor  Sweet,  that  the  nearer  together  we  can 
get  the  supports  and  still  retain  the  condition  of  rigidity  the  less 
we  shall  have  to  depend  upon  the  correctness  of  the  foundations, 


76 


MODERN   LATHE   PRACTICE 


and  this  of  itself  is  a  matter  of  very  important  consideration,  since 
in  some  of  the  popular  forms  of  machines  their  truth  and  correct- 
ness depends  to  a  very  considerable  extent  upon  the  accuracy  and 
continued  stability  of  the  foundations  upon  which  they  rest. 

It  was  from  such  considerations  and  conditions  as  has  just 
been  illustrated  and  described  that  the  author  designed  and  built 
the  21-inch  swing  engine  lathe  shown  in  Fig.  33.  This  lathe  met 
with  exceptional  success  in  the  market  both  in  a  mechanical  and 
financial  way  and  a  large  number  of  them  were  built  and  sold, 
although  they  were  brought  out  during  a  season  of  great  depres- 
sion both  in  mechanical  and  financial  circles,  when  hardly  a  machine 


FIG.  33.  —  A  21-inch  Lathe  with  the  Parabolic  Form  of  Bed. 
Designed  by  the  Author. 

shop  in  the  country  was  running  full  time,  and  many  of  them  but 
eight  hours  a  day  for  three  days  only  in  a  week.  After  a  couple  of 
years  these  beds  were  changed  to  the  rectangular  form  in  order  to 
satisfy  the  demands  of  customers,  the  depth  being  nearly  as  great 
as  the  one  here  shown  is  in  its  deepest  part,  and  the  weight  much 
increased.  The  ends  were  made  square  and  the  rear  box  leg 
made  a  regular  cabinet  similar  to  the  front  cabinet.  The  lathe  is 
still  built  with  very  little  change  in  its  general  design  except  as 
above  specified,  although  it  was  originally  designed  over  a  dozen 
years  ago. 

It  will  be  noticed  in  the  design  shown  in  Fig.  33  that  the  front 
end  of  the  front  cabinet  is  in  a  vertical  line  with  the  front  end  of  the 
head-stock,  as  suggested  by  Professor  Sweet,  and  about  twelve 


LATHE  DESIGN:  THE  BED  AND   ITS  SUPPORTS 


77 


years  before  his  article  was  published,  although  it  is  probable  that 
he  had  held  the  same  opinions  therein  expressed  for  a  much  longer 
period  than  this  would  indicate. 

There  is  much  diversity  of  opinion  as  to  the  proper  method  of 
designing  the  "shears,"  "ways,"  "tracks,"  "V's"  or  by  what- 
ever term  we  may  designate  the  top  portion  of  a  lathe  bed. 

It  has  been  shown  in  the  "old  chain  lathe,"  Fig.  13,  when  beds 
were  made  of  wood,  that  the  V's  were  made  of  strips  of  wrought 
iron  set  on  edge  and  fastened  in  rabbits  cut  in  the  wooden  bed, 
their  upper  edges  chipped  and  filed  in  the  form  of  an  inverted  V. 
There  were  only  two  of  these,  the  head-stock,  tail-stock  and  car- 
riage, all  resting  upon  the  same  V's.  Consequently,  the  carriage 
was  not  able  to  run  past  the  head-stock  or  the  tail-stock,  as  is  the 
case  with  the  modern  lathe-bed  having  four  V's. 

The  usual  form  of  construction  is  shown  in  cross  section  in 
Fig.  34,  which  is  drawn  to  the  usual  proportion  of  the  component 
parts  of  a  bed.  As  a  matter  of 
strength,  stability,  and  rigidity, 
the  center,  at  the  top,  of  the  in- 
side V's  A,  A,  and  the  lathe 
center  or  center  of  the  head 
spindle  B,  should  form  an  equi- 
lateral triangle.  An  arc  C,  of  a 
radius  struck  from  the  center  B, 
and  just  clearing  the  V  at  A, 
will  be  the  radius  of  the  swing  of 
the  lathe 

This  matter  of  determining 
"the  swing"  of  a  lathe  differs 
materially  as  between  the  prac- 
tice of  this  country  and  Eng- 
land. An  English  author,  Mr. 
Joseph  Horner,  states  it  thus : 
"The  'centers'  signifies  the  distance  from  the  top  face  of  the  bed 
to  the  centers  of  the  spindles.  English  and  continental  lathes  are 
designated  thus,  but  American  by  twice  the  centers,  or  the  'swing,' 
in  other  words  —  the  maximum  diameter  which  a  lathe  will  carry 
over  the  bed."  And  with  all  due  respect  to  the  opinions  and  prac- 


FIG.  34.  —  The  Usual  Form  of  Cross 
Section  of  Bed  with  Four  V's. 


78 


MODERN   LATHE  PRACTICE 


tice  of  our  cousins  "on  the  other  side/'  it  would  seem  the  proper 
designation,  and  the  one  in  which  a  prospective  purchaser  would 
be  most  interested,  to  tell  him  how  large  a  piece  of  work  could 
be  done  in  the  lathe,  rather  than  to  tell  him  the  half  of  this  diame- 
ter, or  the  radius,  and  let  him  have  the  trouble  of  the  mental  cal- 
culation of  multiplying  this  dimension  by  two  every  time  it  is 
mentioned.  It  may  seem  all  right  when  one  is  accustomed  to  it, 
but,  like  the  English  monetary  system  of  pounds,  shillings,  and 
pence,  it  seems  unnecessarily  cumbersome  when  compared  with 
the  directness  of  the  American  expression. 

In  order  to  increase  the  swing 
of  the  lathe  without  raising  the 
head  spindle  in  relation  to  the 
bed,  some  builders  prefer  to  omit 
the  inside  V's,  as  shown  in  Fig. 
35,  by  which  means  the  arc  C,  as 
given  in  Fig.  34,  and  here  shown 
as  a  dotted  line,  is  increased  to 
the  arc  D,  and  the  swing  of  the 
lathe  increased  by  twice  this  dif- 
ference. In  this  case  the  head- 
stock  and  the  tail-stock  are  both 
fitted  to  the  flat  top  of  the  bed 
and  also  have  a  projecting  rib  or 
its  equivalent  built  down  and 
fitted  to  the  inside  of  the  inwardly 


FIG.  35. 


-  The  English  Form  of  Bed 
with  only  Two  V's. 


projecting  flange  of  the  top  of  the 
bed.  This  method  of  construc- 
tion is  that  in  use  in  English  and  continental  lathes  and  in  recent 
years  has  been  adopted  by  some  lathe  builders  in  this  country. 

Still  another  method  for  increasing  the  swing  is  shown  in  Fig. 
36.  This  is  by  lowering  the  inside  V's,  upon  which  the  head- 
stock  and  tail-stock  rest,  and  leaving  the  outer  V's  supporting  the 
carriage  in  their  original  position.  In  this  engraving  the  arcs, 
representing  the  radius  of  the  swing  in  the  two  former  examples, 
are  shown  in  dotted  lines,  and  the  increased  arc  E  by  a  full  line. 
There  are  other  advantages  in  the  form  of  construction  shown  in 
Figs.  35  and  36,  which  will  be  noticed  later  on. 


LATHE  DESIGN:  THE  BED   AND   ITS  SUPPORTS 


79 


In  Fig.  37  is  shown  the  form  of  bed  adapted  by  Lodge  &  Shipley, 
which  will  be  seen  to  be  a  modification  of  the  preceding  examples 
in  that,  in  this  case,  the  English  form  of  a  flat  surface  is  used  in 
place  of  the  front  V,  while  at  the  rear  the  inverted  V-shape  is 
retained.  There  are  several  advantages  in  this  form.  The  rear 
V  is  preferred  by  some  as  a  better  method  of  locating  the  head- 
stock  and  tail-stock  in  perfect  alignment,  inasmuch  as  that  while 
the  head-stock,  once  located  and  securely  bolted  down,  remains  in 
its  fixed  position  whether  resting  on  V's  or  upon  a  flat  surface  and 


FIG.  36.  —  Bed  with  Depressed  Inside 
V's,  giving  Increased  Swing. 


FIG.  37.  —  The  Lodge  &  Shipley 
Form  of  Bed. 


between  vertical  faces  as  in  the  English  lathe.  With  the  movable 
tail-stock  this  is  different.  There  is  a  constant  tendency  to  wear 
in  all  directions  of  contact,  and  if  fitted  between  vertical  surfaces 
this  tendency  will  in  time  throw  it  out  of  line.  When  resting  upon 
the  inclined  surfaces  of  the  inverted  V,  the  wear  is  likely  to  be 
equal  on  the  two  sides  and  the  lateral  alignment  is  maintained, 
while  the  vertical  wear  will  be  considerably  less  than  that  of  the 
head  spindle  in  the  boxes,  which  should  be  vertically  adjustable 
to  compensate  for  this  wear  and  so  a  proper  and  perfect  alignment 
of  the  two  be  maintained. 

The  bed  shown  in  Fig.  37  is  considerably  deeper  than  the  former 


80 


MODERN   LATHE   PRACTICE 


examples,  but  corresponds  very  nearly  to  the  proportions  that  have 
been  found  necessary  to  the  proper  strength  and  rigidity  of  the 
modern  lathe  when  used  under  the  severe  strains  and  hard  usage 
incident  to  modern  shop  methods  and  to  the  use  of  high-speed 
tool  steels,  with  the  necessity  for  the  rapid  reduction  of  the  diameter 
of  the  stock  which  would  in  former  times  have  been  considered 
very  wasteful  of  materials,  but  which  in  these  days  of  cheap  ma- 
chine steel  are  much  more  economical  than  the  usual  processes 
of  forging  the  parts  to  nearly  the  diameters  necessary,  as  was 
formerly  the  usage  when  the  price  of  steel  was  very  much  above 
what  it  is  now  and  the  cost  of  labor  considerably  less. 

It  will  have  been  noticed  in  the  engravings  of  the  cross  sections 
or  beds  thus  far  given,  that  the  "side  plates"  or  outer  walls  have 
been  uniform  on  the  two  sides  and  across  the  ends.  Also,  that  the 
bed  is  very  much  strengthened  by  the  track  or  flat  upper  member. 
To  obtain  a  casting  of  nearly  uniform  shrinkage  throughout,  and 
to  diminish  as  much  as  may  be  the  unequal  strains,  as  well  as  to 

add  to  the  strength  and 
stiffness  of  the  bed,  the 
lower  edge  has  been  reen- 
forced  by  an  additional 
thickness  for  a  short  dis- 
tance from  the  lower  edge. 
This  has  been  made  of 
different  forms  by  different 
designers,  but  is  substan- 
tially as  shown  in  these 
engravings. 

In  Fig.  38  is  shown  an 
ideal  form  of  bed  combin- 
ing great  strength  and 
stiffness  with  a  minimum  amount  of  material  when  its  rigidity 
is  considered.  Much  is  said  in  machine  tool  design  of  the  "box 
form,"  and  while  in  some  instances  its  merits  may  have  been  over- 
rated it  certainly  is  a  form  possessing  most  excellent  qualities  of 
strength,  stiffness,  and  power  to  withstand  torsional  strains  as 
well  as  to  rigidly  support  heavy  loads.  It  is  for  these  reasons  that 
this  bed  is  designed  as  it  is,  and  for  these  reasons  it  seems  fair  to 


FIG.  38. 


-  Ideal  Form  of  Bed  to  Resist 
Torsional  Strains. 


LATHE  DESIGN:  THE   BED   AND   ITS  SUPPORTS 


81 


call  it  an  ideal  form.  The  entire  length  of  the  sides  or  "  side  plates," 
are  double,  or  of  the  "box  form,"  tied  together  at  frequent  inter- 
vals so  that  the  outer  and  inner  wall  properly  support  each  other. 
To  "  balance  the  casting,"  there  is  not  only  an  additional  thickness 
of  metal  at  the  bottom  of  the  outer  wall,  on  the  outside,  but  an 
inwardly  projecting  flange  along  the  inside  of  the  inside  wall  at 
the  bottom.  As  far  as  possible  the  casting  and  all  its  component 
parts  are  of  as  nearly  as  may  be  the  same  thickness,  so  as  to  reduce 
to  a  minimum  the  internal  strains  of  the  casting  as  it  cools  after 
being  "poured." 

A  further  reference  to  the  form  and  disposition  of  the  cross- 
braces  or  cross-ties  is  made  a  little  further  on  in  describing  these 
members  of  the  casting. 

Thus  far  the  cross  section  of  the  bed,  and  its  component  parts 
of  the  side  plates,  the  track  or  top  portion  and  the  V's,  have  been 


Iba 


FIG.  39.  —  Forms  of  Cross-Ties  or  Braces. 


shown,  in  addition  to  the  front  elevations  and  the  various  forms 
of  beds  for  supporting  the  weight  of  the  head-stock,  the  tail-stock, 
and  the  carriage.     The  next  feature  to  be  considered  will  be  the 
"cross-bars,"  or  "cross-ties"  as  they  are  sometimes  called. 

The  cross  sections  of  these  various  forms  are  shown  in  Fig.  39 
at  A,  B,  C,  D,  and  E,  which  give  the  principal  forms  in  common 
use.  At  A  is  the  simple  form  or  single  bar,  set  on  edge  and  used  in 
the  earlier  forms  of  cast  iron  lathe  beds  for  many  years.  The 
desire  to  get  some  form  more  rigid  laterally  led  to  the  addition  of  a 
horizontal  rib,  first  on  the  top  edge  only  and  then  on  the  bottom  also, 
making  the  I-beam  section  shown  at  B.  This  was  for  many  years 
considered  quite  sufficient  for  the  purpose  until  the  desire  for  more 
strength  and  stiffness  led  to  the  adoption  of  the  "box  form"  shown 
at  C.  Later  on  this  form  was  still  further  strengthened  by  the 
addition  of  outwardly  projecting  ribs  or  flanges  at  the  bottom 


82 


MODERN   LATHE   PRACTICE 


edges  forming  the  section  that  is  shown  at  D.  To  this  form  has 
since  been  added  the  top  ribs  as  shown  at  E,  and  the  question  has, 
for  the  time  at  least,  been  solved,  of  making  as  strong  and  rigid  a 
cross-bar  as  is  possible. 

It  will  be  noticed  that  wherever  these  forms  are  with  double 
walls  the  internal  space  is  closed  at  the  top.  This  occurs,  first,  as 
the  bed  is  cast  bottom  side  up,  and  it  is  more  convenient  to  pour 
the  molten  iron  into  this  form  and  have  a  solid  casting;  it  gives  a 
better  appearance  to  the  top  of  the  cross-bar  in  the  finished  lathe; 
and  a  cross-bar  open  at  the  top  would  furnish  a  receptacle  for  dirt, 
chips,  and  small  articles  that  would  occasionally  drop  into  it. 

These  cross-bars  were  located  at  right  angles  to  the  length 
of  the  bed  as  shown  in  plan  in  Fig.  40,  their  distances  apart  in 


FIG.  40.  —  The  Usual  Manner  of  Placing  the  Cross-Ties. 

the  earlier  forms  of  beds  being  two  or  three  times  the  width  of  the 
center  of  the  bed.  This  distance  was  gradually  reduced  as  the 
beds  were  made  heavier  and  stronger,  until  ten  or  fifteen  years 
ago  it  was  frequently  the  case  that  the  cross-braces  were  spaced  con- 
siderably less  distance  apart  than  the  width  of  the  bed,  particularly 
in  the  wider  beds  used  for  heavy  lathes,  say  from  36-inch  swing 
and  larger.  This  method  of  locating  them  prevailed  in  the  use 
of  the  forms  shown  in  cross  section  at  A,  B,  and  C,  Fig.  39. 

As  still  stronger  and  more  rigid  beds  were  called  for,  the  braces 
were  placed  at  an  angle,  generally  crossing  each  other,  and  of  the 
form  and  proportion  shown  in  plan  in  Fig.  41.  In  this  case  it  was 
usual  to  use  the  forms  shown  in  cross  section  at  B,  C  and  D,  Fig.  39. 
The  angle  at  which  these  were  set  was  varied  by  different  builders, 
that  here  shown  being  45  degrees,  and  the  most  usual  angle  used. 

In  Fig.  42  is  shown  a  plan  of  the  ideal  bed,  a  cross  section  of 
which  is  shown  in  Fig.  38.  These  cross-braces  are  made  of  the 


LATHE   DESIGN:  THE   BED   AND   ITS   SUPPORTS 


83 


sectional  form  shown  in  Fig.  39,  at  E,  and  are  placed  at  an  angle 
of  30  degrees  with  the  side  of  the  bed,  and  in  the  illustration  the 
spaces  between  the  walls  of  the  braces  as  well  as  the  bed  are  shown, 
and  also  the  proper  spacing  from  the  head  end  of  the  bed.  It 
will  be  readily  seen  that  such  a  form  of  casting  insures  great  stiff- 
ness and  rigidity  and  guarantees  the  casting  against  torsional 


FIG.  41.  —  Angular  Bracing  with  the  Cross-Ties. 

strains,  as  well  as  against  unequal  strains  as  the  casting  is  cooling. 
As  a  matter  of  design  in  providing  a  rigid  bed  this  form  seems  to 
realize  all  the  desirable  qualities  that  leave  nothing  more  to  be 
desired.  Yet  it  is  possible  that  in  the  continual  development  of 
the  lathe,  better  methods  and  stronger  beds  will  be  brought  out, 
for  what  we  consider  to  be  of  ample  strength  to-day  may  be 
relegated  to  the  scrap-heap  a  dozen  years-  from  now. 


FIG.  42.  —  Ideal  Manner  of  Arranging  Angular  Bracing  with  Cross-Ties. 

The  form  of  the  " track"  or  upper  portion  of  the  lathe  bed  has 
much  to  do  with  the  form  and  strength  of  the  carriage  which  it 
supports.  In  the  early  form  of  wooden  beds,  with  two  V's  formed 
from  wrought  iron  bars  set  upon  edge  and  chipped  and  filed  to 
the  inverted  V  form,  with  the  head-stock,  tail-stock,  and  carriage 
all  resting  upon  them,  the  carriage  had,  of  necessity,  to  be  made 


84 


MODERN  LATHE   PRACTICE 


with  scant  bearing  on  the  V's,  that  is,  very  narrow,  measured 
along  the  length  of  the  bed,  as  it  could  not  pass  the  head-stock  and 
the  tail-stock  as  the  "wings"  of  the  carriage  do  in  the  later  forms 
of  bed  with  four  V's,  or  their  equivalent.  Consequently,  the  head 
center  of  the  lathe  had  considerably  more  " overhang"  than  it  has 
at  present,  in  order  to  permit  the  tool  to  be  worked  up  near  the 
lathe  center;  and  the  same  was  true  of  working  up  closely  to  the 
tail-stock  center. 

With  the  advent  of  cast  iron  beds  four  V's  were  usually  pro- 
vided for.  Whether  the  idea  of  four  V's  came  in  with  the  cast 
iron  bed  is  not  certain,  as  it  is  entirely  possible  that  some  ingenious 
machinist  fitted  the  wrought  iron  strips,  not  only  to  the  inside  but 
to  the  outside  of  the  two  wooden  beams  composing  the  bed,  and  so 


FIG.  43.  —  A  Carriage  on  a  Bed  with  Inside  V's. 


accomplished  the  same  results  as  to  providing  a  "wing  carriage," 
capable  of  passing  the  head-stock  and  the  tail-stock  as  we  have 
them  to-day. 

The  lathe  bed  with  four  V's  and  the  carriage  suitable  for  it  is 
shown  in  Fig.  43,  by  which  it  will  be  seen  that  the  portion  of  the 
carriage  coming  over  the  inside  V's  at  A  must  be  cut  away  so  as 
to  clear  them  entirely,  as  the  carriage  must  rest  wholly  upon  the 
outer  V's.  The  necessity  for  this  cutting  away  to  clear  the  inside 
V's  is  a  source  of  weakness  to  the  carriage,  and  the  only  way  to 
compensate  for  it  is  to  make  this  part  of  the  carriage  broader, 
which  does  not  add  much  to  its  strength,  or  to  make  it  deeper,  which 
lessens  the  capacity  of  the  lathe  by  decreasing  its  possible  "swing 
over  the  carriage." 

In  Fig.  44  is  shown  the  effect  when  the  inside  V's  are  omitted, 
and  the  carriage  at  A  may  be  made  of  much  greater  strength  with- 
out raising  its  top  line  so  as  to  decrease  the  swing  over  the  carriage. 


LATHE  DESIGN:  THE  BED  AND   ITS  SUPPORTS 


85 


It  is  clear  that  so  far  as  the  convenience  of  design  and  the  strength 
of  the  carriage  is  concerned  this  form  of  bed  is  preferable  to  the 
one  having  four  Vs.  There  is  one  disadvantage,  however,  which 
occurs  in  fitting  the  head-stock  and  the  tail-stock  to  this  vertical 
inner  surface  of  the  " track"  at  B,  B.  The  head-stock,  being  fixed 
to  the  bed,  may  be  tightly  fitted  and  remain  so,  but  the  tail-stock, 


FIG.  44.  —  A  Carriage  on  a  Bed  when  Inside 
V's  are  Omitted. 

from  its  being  a  movable  part  and  frequently  run  back  and  forth, 
will  in  time  wear  sufficiently  to  throw  its  center  out  of  line  with 
the  center  of  the  head  spindle.  This  disadvantage  may  be  obvi- 
ated by  making  these  vertical  surfaces  B,  B,  slightly  inclined. 

This  inclination  to  the  inner  surfaces  of  the  track  of  the  bed  is 
shown  in  Fig.  45,  which  gives  the  form  of  a  carriage  when  designed 
to  fit  the  ideal  form  of  bed  shown  in  Figs.  38  and  42.  In  this  case 


FIG.  45.  —  Form  of  Carriage  for  Ideal  Form  of  Bed. 

the  full  strength  of  the  carriage  is  maintained  and  a  second  support 
is  furnished  it  inside  of  the  outer  V  at  the  front  and  back  by 
the  contact  of  flat,  horizontal  surfaces  in  the  place  where  the  inside 
V  would  be  in  the  form  of  bed  having  four  V's.  This  construc- 
tion shortens  very  much  the  "span"  of  the  carriage  between 
supports  and  consequently  renders  it  much  more  stiff  and  rigid, 


86  MODERN  LATHE  PRACTICE 

adapting  it  to  much  more  severe  strains  in  heavy  work  than  either 
style  of  carriage  preceding  it.  In  fact  it  is  the  strongest  carriage 
now  known,  in  proportion  to  its  weight. 

The  form  and  proportions  of  the  lathe  bed  having  been  duly 
considered,  its  different  component  parts  illustrated  and  described, 
and  these  detail  matters  criticised  and  commented  upon,  the  next 
part  of  the  lathe  to  be  dealt  with  would  naturally  seem  to  be  the 
legs,  cabinets,  or  like  supports  upon  which  the  bed  is  to  rest. 

The  usual  height  of  the  centers  of  a  lathe  from  the  floor  is  about 
43  inches,  and  in  designing  lathes  this  height  is  maintained  without 
regard  to  the  capacity  or  swing  of  the  lathe  until  its  swing  becomes 
so  large  that  with  the  bed  resting  on  a  properly  built  foundation  on 
a  level  with  the  floor,  it  becomes  necessary  to  raise  this  height 


FIG.  46.  —  Early  Form  of  Cast  Iron  Legs  with  Braces. 


sufficiently  to  obtain  a  bed  of  proper  depth  and  a  head-stock  of 
sufficient  swing  to  meet  the  requirements. 

Therefore  the  smaller  the  capacity  of  the  lathe  the  higher  will 
be  the  legs  or  other  supports  under  the  bed. 

In  the  early  style  of  wooden  beds,  these  supports  were  simply  legs 
of  square  timber  bolted  to  the  bed  and  either  vertical  or  spread  out 
at  the  floor,  according  to  the  notion  of  the  builder.  When  cast  iron 
beds  came  to  be  used  the  legs  were  also  of  cast  iron  and  of  rather 
frail  design.  Later,  when  the  necessity  for  more  rigidity  was  found 
desirable,  not  only  the  beds  but  their  supporting  legs  were  made 
heavier. 

In  a  shop  near  Boston  was  found  a  lathe  provided  with  an  ex- 
ample of  the  earlier  form  of  cast  iron  legs  strengthened  by  cast  iron 
braces  as  shown  at  A,  A,  A,  A,  Fig.  46.  The  lathe  was  12-inch 
swing  and  of  the  hand  lathe  pattern,  with  a  wooden  cone  pulley 


LATHE  DESIGN:  THE  BED   AND   ITS  SUPPORTS          87 

on  the  spindle,  probably  built  about  1840.  The  legs  were  quite 
light,  the  different  members  being  about  j  inch  thick  and  2  inches 
wide.  The  braces  were  of  the  same  dimensions  and  secured  at  the 
ends  by  J-inch  "tap  bolts"  of  the  old  square-head  style,  the  ends  of 
the  braces  being  thickened  somewhat  to  accommodate  them. 

How  this  lathe  happened  to  endure  the  wear  and  tear  of  shop 
use  for  so  many  years  without  the  legs  being  broken  is  a  mystery. 
Their  frail  and  slender  appearance  beside  the  modern  deep  bed, 
supported  by  heavy  cabinet  legs,  is  an  object  lesson  in  the  practical 
evolution  of  the  American  lathe. 

With  the  continually  increasing  weight  and  rigidity  of  the  lathe 
beds  to  meet  the  hard  service  of  modern  shop  methods  and  high- 
speed steels,  first  represented  by  the  Mushet  tool  steel,  it  became 
necessary  to  furnish  much  better  supports  for  the  lathe  beds,  and 
the  fact  was  apparent  that  these  supports  must  extend  for  a  greater 
distance  along  the  length  of  the  bed  than  the  older  form  of  legs  ever 
had.  At  this  time  there  were  several  of  the  different  machine  tools 
supported  on  a  " cupboard  base,"  or  a  base  of  rectangular  form- 
having  a  door  giving  access  to  its  interior  for  the  purpose  of  stowing 
away  tools,  change-gears,  wrenches,  and  like  articles.  This  form 
of  base  was  prominently  used  in  the  Universal  Milling  Machine. 
Whether  the  " cabinets"  for  supporting  a  lathe  bed  were  suggested 
by  this  use  of  them  or  not  does  not  appear,  although  it  seems  prob- 
able. We  know  that  wooden  cupboards  had  been  used  under 
lathes,  being  fastened  to  the  legs  and  used  for  the  same  purposes  as 
the  cabinets  or  cupboards  formed  in  the  bases  or,  as  sometimes 
called,  the  " standards"  or  columns  of  the  later  machines. 

At  the  present  time  a  number  of  lathe  builders  still  use  the  old- 
style  legs,  made  heavier  and  with  the  material  better  distributed 
for  strength,  and,  as  a  rule,  the  top  portion  of  the  leg  extending 
farther  along  on  the  under  side  of  the  bed  for  the  purpose  of  giving 
better  support. 

It  is  also  the  case  that  the  cabinet  form  of  bed  supports  is  used 
more  upon  expensive  lathes,  such,  for  instance,  as  those  designed 
more  particularly  for  tool  room  and  precision  work.  For  turret 
lathes  and  screw  machines  they  are  also  much  used,  and  are  often 
cast  as  an  integral  portion  of  the  bed  itself  instead  of  being  made  as 
a  separate  piece  and  bolted  on. 


88  MODERN   LATHE   PRACTICE 

Cabinet  supports  for  lathe  beds  are  made  in  various  forms  by 
the  several  builders,  some  of  which  will  be  illustrated  in  this  chapter. 
These  will  be  such  as  have  some  general  features  common  to  nearly 
all  of  them,  and  in  addition  a  few  of  the  forms  having  special 
features. 

The  correct  principle  governing  the  dimensions  of  cabinet 
supports  should  be  properly  understood.  Obviously,  the  reasons 
for  substituting  cabinets  for  the  earlier  form  of  legs  was  to  obtain 
a  better  support.  It  was  certainly  possible  to  so  design  the  leg  as 
to  amply  support  the  weight  of  the  lathe  and  all  that  could  be  put 
upon  it  by  way  of  work  to  be  done  by  it.  The  disadvantage 
was  that  a  leg  placed  at  each  end  of  the  bed  and  extending  only  a 
short  distance  along  under  it  left  a  long  stretch  of  bed  with  no 


7 


FIG.  47.  —  Lathe  Bed  Supported  by  Old  Style  Legs. 

support  at  all.  This  necessitated  "  center  legs  "  and,  in  a  long  lathe, 
two  or  three  of  them.  Under  these  conditions  it  was  a  difficult 
matter  to  so  set  up  a  lathe  that  these  center  legs  should  all  sit 
level  and  support  the  bed  in  a  correct,  level,  straight  line. 

These  difficulties  are  in  a  great  measure  avoided  in  the  lathes 
provided  with  cabinet  supports.  In  Fig.  47  the  effect  of  the  old- 
style  legs  is  seen.  Attention  is  called  to  the  fact  that  the  head- 
stock  is  only  supported  by  the  leg  at  the  outer  end,  while  the  point 
at  the  front  journal  where  the  heaviest  weight  comes  has  no  sup- 
port whatever  from  the  leg.  The  same  may  be  said  in  a  lesser 
degree  of  the  rear  end,  where  the  tail-stock  has  only  partial  support 
in  a  similar  manner.  And  when  the  tail-stock  is  moved  out  of  its 
extreme  rear  position  the  case  is  much  worse  and  identical  with 
that  of  the  head-stock.  This  condition  will,  of  course,  necessitate 
the  use  of  a  center  leg,  which  if  not  supported  upon  the  floor  or 


LATHE  DESIGN:  THE  BED  AND   ITS  SUPPORTS         89 

foundation  in  a  perfectly  correct  position  will  do  as  much  harm  as 
good.  If  it  is  too  low  it  will  be  of  no  benefit  since  the  center  of  the 
bed  may  sink  under  the  weight,  and  strain  of  the  work  upon  the 
carriage.  If  it  is  too  high  the  lathe  will  be  thrown  out  of  line. 

In  sharp  contrast  to  these  conditions  is  the  bed  shown  in  Fig. 
48.  In  this  case  the  front  cabinet  is  of  a  length  on  the  bed  equal  to 
the  length  of  the  head-stock,  hence  the  front  bearing  of  the  head 
spindle  has  a  support  of  solid  iron  down  to  the  foundation,  or  floor 
upon  which  the  cabinet  supports  rest.  The  tail-stock  is  similarly 
supported  by  a  cabinet  occupying  the  distance  equal  to  its  length 
upon  the  bed.  An  argument  in  favor  of  this  method  of  sup- 
porting the  bed  is  not  necessary  as  the  conditions  are  self-evident. 


FIG.  48.  —  Form  and  Proportions  of  Cabinet  Supports. 

But  there  is  still  another  reason  why  the  cabinet  support  is 
the  more  rigid,  and  that  is  the  fact  that  with  the  long  distance  on 
the  bed  to  which  the  cabinet  is  firmly  and  solidly  bolted  comes 
additional  stiffness  and  rigidity,  not  only  in  a  vertical  direction  for 
sustaining  weights,  but  also  to  withstand  the  torsional  strains  to 
which  every  lathe  bed  is  subjected,  and  which  are  multiplied  rapidly 
as  we  load  the  lathe  with  heavier  work,  take  heavier  cuts,  and  use 
high-speed  tool  steel,  by  which  much  greater  speed  may  be  used. 

The  next  matter  to  be  considered  is  the  form  of  the  cabinet, 
although  this  is  a  secondary  consideration,  the  first  being  that  we 
have  the  cabinet  and  that  it  reaches  out  under  the  bed  to  the  prac- 
tical length  as  shown  in  Fig.  48. 

For  small  lathes,  say  from  12  to  20-inch  swing,  the  cabinet  is 
frequently  made  nearly  square  While  this  is  wrong  in  theory,  as 
has  just  been  explained,  it  is  an  improvement  upon  the  old-style 


90 


MODERN   LATHE   PRACTICE 


leg.  The  form  shown  in  Fig.  48  is  substantially  that  used  by 
Lodge  &  Shipley  in  their  smaller  lathe.  Its  peculiar  feature  is 
the  strength,  vertical  end  walls,  without  projections  at  the  base, 
while  the  regular  projection  is  made  in  the  front  and  the  rear.  This 
form  is  less  expensive  in  its  pattern  work  and  somewhat  easier  to 
mold,  but  its  appearance  is  not  as  good  as  the  one  shown  in  Fig.  50 


FIG.  49.  —  The  Lodge 
&  Shipley  Cabinet 
for  Small  Lathes. 


FIG.  50.  —  Ideal  Form  of 
Small  Lathe  Cabinet. 


which  has  equal  projections  on  all  four  sides  and  at  the  top  and 
bottom,  thus  giving  it  a  more  symmetrical  appearance.  It  may 
have  only  three  sides  enclosed,  the  side  walls  turning  the  corner 
for  only  an  inch  or  so,  and  this  side  be  placed  underneath  the  lathe 
bed,  as  is  now  done  by  some  of  the  builders.  But  as  this  cut-away 
portion  would  come  directly  under  that  point  of  the  head-stock 
where  the  most  support  is  needed,  it  is  of  doubtful  utility  to  cut  it 
away,  or  to  reduce  the  support  of  solid  iron  at  this  point. 


FIG.  51.  —  Cabinet  and  Cupboard. 

Lathes  for  light  work,  of  12  to  18-inch  swing,  may  be  supported 
by  square  cabinets,  but  if  for  heavy  duty  and  continuous  hard 
work  the  cabinets  should  be  considerably  longer  than  they  are 
wide  and  support  the  bed  as  shown  in  Fig.  47. 

In  Fig.  51  is  shown  a  form  for  head  and  tail  cabinets,  or  "  Cabinet 


LATHE  DESIGN:  THE  BED  AND  ITS  SUPPORTS 


91 


and  Cupboard,"  for  medium-sized  lathes,  say  from  20  to  28-inch 
swing.  These  answer  the  conditions  as  represented  in  Fig.  48,  and 
are  not  excessively  expensive.  They  also  furnish  one  closed  cabinet 
and  an  open  cupboard,  both  of  which  are  available  for  storing  tools, 
gears,  and  similar  articles.  The  arched  opening  at  A  affords  a 


FIG.  52.  —  The  Lodge  &  Shipley  Form  of  Cabinet 
for  Large  Lathes. 

convenient  space  for  introducing  a  lever  or  bar  for  the  purpose  of 
moving  the  lathe.  This  arch  should  be  placed  in  the  cabinets  of  all 
but  the  smallest  ones,  and  even  in  them  a  small  arch  suitable 
for  the  use  of  a  crowbar  will  be  found  convenient. 

In  either  of  the  styles  of  cabinets  shown  the  shelves  may  be 
cast  in,  but  the  usual  method  is  to  cast  strips  upon  which  the  ends 
of  wooden  shelves  may  rest,  thus  making  not  only  the  pattern 
work  but  the  foundry  work  more  simple  and  economical. 


FIG.  53.  —  The    Hendey-Norton    Form    of   Cabinet 
for  Large  Lathes. 

In  Fig.  52  is  shown  the  form  of  cabinet  used  by  Lodge  &  Shipley 
for  large  lathes  and  which  gives  an  excellent  support  to  the  bed  and 
its  superstructure. 

In  Fig.  53  is  shown  a  similar  cabinet  used  by  the  Hendey-Norton 
Company,  differing  from  the  last  one  in  having  the  inner  end  cut 
away.  This  cabinet  does  not,  of  course,  admit  of  the  introduction 


92  MODERN   LATHE  PRACTICE 

of  shelves.  In  the  larger  lathe,  say  from  30  to  40-inch  swing,  inclu- 
sive, doors  are  not  usually  provided,  as  the  height  does  not  admit 
of  it.  Above  40-inch  swing  the  bed  usually  rests  directly  upon  the 
foundation. 

The  cabinets  here  shown  are  given  simply  as  examples,  but 
they  give  a  good  idea  of  the  forms  used  by  most  of  the  modern 
lathe  builders  at  the  present  time,  and  the  reasons  for  their  con- 
tinued and  enlarged  use.  It  is  altogether  probable  that  the  future 
will  witness  an  increase  rather  than  a  decrease  in  the  use  of  the 
cabinet  for  supporting  machines  of  all  kinds  where  it  is  possible 
to  introduce  them,  on  account  of  their  great  rigidity  in  proportion 
to  the  weight  of  cast  iron  used,  as  well  as  the  fact  that  they  furnish 
a  safe  and  convenient  receptacle  for  tools. 


CHAPTER  V 

LATHE  DESIGN;  THE  HEAD-STOCK  CASTING,  THE  SPINDLE  AND  THE 

SPINDLE  CONE 

Design  of  head-stock  for  wooden  bed  lathes.  Early  design  for  use  on  a  cast 
iron  bed.  An  old  New  Haven  head-stock.  The  arch  form  of  the  bottom 
plate.  Providing  for  reversing  gears.  The  Hendey-Norton  head-stock. 
The  Schumacher  &  Boye  head-stock.  The  Le  Blond  head-stock.  The 
New  Haven  head-stock.  The  arch  tie  brace  of  the  new  Hendey-Norton 
design.  Generalities  in  describing  a  lathe  spindle.  Designing  a  spindle. 
Governing  conditions.  The  nose  of  the  spindle.  Spindle  collars.  Proper 
proportions  for  lathe  spindles.  Large  versus  long  bearings.  Design 
of  the  spindle  cone. 

THE  subject  of  lathe  design  is  continued  by  the  consideration 
of  the  design  and  construction  of  the  head-stock,  which  in  some 
respects  is  the  most  important  part,  and  with  it  and  the  parts  which 
go  to  make  up  the  complete  head-stock,  the  most  important 
group  of  parts  in  the  lathe. 

In  the  earlier  form  of  lathes  this  piece  was,  like  most  of  the 
other  parts,  simple  and  crude  in  design  as  well  as  in  the  workman- 
ship bestowed  upon  it.  It  generally  consisted  of  a  base  and  the 
two  upright  ends  in  which  provision  was  made  to  receive  the  boxes, 
and  when  wooden  beds  were  thought  sufficient  for  a  lathe  a  strip 
was  added  beneath  that  filled  the  space  between  the  two  timbers 
forming  the  bed.  Such  a  design  for  a  head-stock  is  shown  in  Fig. 
54,  which  is  taken  from  an  old  lathe  that  did  many  years'  service  in 
a  general  repair  shop.  It  will  be  noticed  that  the  housing  for  the 
spindle  boxes  do  not  have  square  edges,  but  are  of  V-shaped  form. 
They  were  finished  with  a  file  only  and  the  boxes  made  of  cast  iron, 
filed  to  a  fit  and  lined  with  babbitt  metal  which  was  said  to  have 
been  poured  around  the  lathe  spindle  after  it  was  finished,  set  in 
place,  and  lined  up  as  well  as  might  be  with  the  crude  appliances 

93 


94 


MODERN   LATHE   PRACTICE 


at  hand.  The  top  portion  of  the  boxes  were  held  down  by  a  straight 
bar  cap  with  two  holes  which  fitted  over  fixed  threaded  studs 
that  had  been  cast  into  the  head-stock  for  this  purpose. 

The  lathe  was  devoid  of  a  back  gear  and  the  spindle  carried  a 
three-step  cone,  the  largest  part  of  which  was  as  large  as  was  possible 
to  get  into  the  head,  and  a  belt  quite  wide,  considering  the  power 
then  thought  necessary  to  drive  a  lathe  carrying  the  diminutive 
chip  which  was  considered  proper  for  a  lathe  to  take  at  the  time  this 
lathe  was  in  use. 

Later  on,  when  the  cast  iron  bed  was  adopted  and  when  back 
gears  were  added  to  the  lathe,  the  requirements  of  additional 
strength  were  recognized  and  not  only  the  base  plate,  but  the  up- 


FIG.  54.  —  Early  Form  of  Head-Stock  for  Wooden 
Lathe  Bed. 


rights  or  housings  at  the  front  and  rear  end,  were  made  thicker  and 
heavier.  One  of  these  head-stocks  is  shown  in  Fig.  55,  which 
gives  a  good  general  idea  of  the  form  of  the  casting  and  shows  also 
a  strengthening  brace  A.  While  it  would  seem  at  first  thought 
more  necessary  to  brace  the  housing  of  the  front  box  than  that 
carrying  the  rear  journal,  it  should  be  remembered  that  the  latter 
must  withstand  the  strain  of  the  " thrust"  or  endwise  pressure  of 
the  spindle  due  to  holding  work  upon  centers,  and  the  pressure  of 
drilling  work,  one  end  of  which  is  held  in  a  chuck  and  the  other  in 
a  center  rest,  and  similar  kinds  of  work.  While  in  the  modern 
lathes  this  thrust  device  is  usually  a  part  of  the  rear  box,  the  earlier 
method  was  to  fix  two  studs  in  the  rear  of  the  head-stock,  one  in 


LATHE   DESIGN:  THE   HEAD-STOCK  CASTING,   ETC.      95 

each  side  of  the  rear  box  and  on  a  horizontal  line  with  it,  and  across 
these  to  fix  a  strong  bar  carrying  an  adjustable  thrust  screw  for 
taking  the  end  thrust  of  the  spindle.  The  details  and  design  of 
this  important  device  will  be  taken  up  further  on. 


FIG.  55.  —  A  Later  Form  of  Head-Stock  with  Back 
Gears  and  a  Strengthening  Brace. 

In  Fig.  56  is  shown  a  peculiar  form  of  head-stock  upon  an  old 
lathe  in  one  of  the  older  shops  in  New  Haven,  Conn.  The  lathe 
was  broken  up  for  old  iron  after  an  indefinite  period  of  idleness. 
It  was  of  about  16-inch  swing  and  the  various  members  of  the  head- 
stock  were  about  one  and  one-half  inches  square.  The  bed  of  the 
lathe,  and  the  legs  which  supported  it,  were  of  cast  iron  and  very 
much  like  those  shown  in  Fig.  46.  The  head  was  provided  with 
back  gears  of  very  light  design  and  the  lathe  had  a  lead  screw  and 


FIG.  56.  —  Form  of  Head-Stock  on  Old  Lathe  found 
in  New  Haven,  Conn. 

feed-rod  adapting  it  for  thread  cutting.     It  was  undoubtedly  con- 
sidered a  proper  engine  lathe  "in  its  day." 

The  next  form  of  head-stock  which  followed  that  shown  in  Fig. 
55  seems  to  have  been  of  the  form  shown  in  Fig.  57.    In  this  case 


96  MODERN  LATHE  PRACTICE 

the  base  of  the  casting  was  raised  in  arch-like  form  and  the  under 
side  recessed  to  the  same  form  so  as  to  maintain  an  equal  thickness 
of  metal  throughout.  This  form  seems  to  have  been  a  favorite  one 
and  many  lathes  were  built  by  various  makers  with  substantially 
this  form,  the  variations  from  it  not  being  of  sufficient  importance 
to  justify  a  further  classification. 

As  yet  the  housings  had  not  been  made  thick  enough  to  suggest 
coring  them  out  in  order  to  save  iron  or  for  the  purpose  of  avoid- 
ing unequal  contraction  of  the  metal  upon  cooling  after  casting, 
by  making  all  members  of  the  casting  of  as  nearly  an  equal  thick- 
ness as  possible.  Of  late  years  these  points  have  received  much 
attention  and  study  by  the  designers  of  machine  tools,  and  rightly 


FIG.  57.  —  One  of  the  Older  Favorite  Forms  of 
Head-Stock. 

so,  as  their  importance  was  to  a  large  extent  overlooked  in  the 
earlier  designs,  the  reason  probably  being  that  all  castings  were 
made  so  much  lighter  and  had  much  less  strain  to  withstand  in  the 
regular  service  to  which  the  machine  was  put. 

In  Fig.  58  is  shown  a  modification  of  the  arch  form  shown  in 
Fig.  57,  which  has  for  its  purpose  the  strengthening  obtained  by 
the  rib  A  in  Fig.  55,  only  in  a  better  form,  as  the  method  is  "  cored 
out,"  or  formed  with  a  " green  sand  core"  under  the  head-stock,  so 
as  to  provide  for  an  equal  thickness  of  metal  over  the  entire  base. 
This  raised  portion  could  be  introduced  quite  conveniently  as  the 
small  end  of  the  spindle  cone  was  located  over  it,  thus  insuring 
ample  space  for  building  it  up. 

In  the  examples  thus  far  shown  of  lathe  heads  the  feed  gears 


LATHE  DESIGN:  THE   HEAD-STOCK  CASTING,   ETC.       97 

were  located  outside  the  housings,  except  in  the  case  of  that  shown 
in  Fig.  56.  As  the  change  came  to  be  made  of  locating  "  tumbler 
gears,"  or  reversing  gears,  inside  of  the  housing,  it  naturally  fol- 
lowed that  the  metal  of  the  head-stock  base  must  be  cut  away 
under  that  part  of  the  main  spindle  upon  which  *was  fixed  the 
spindle  gear  or  feed  gear  from  which  the  feed  mechanism  was 
driven.  This  was  the  case  for  perhaps  fifty  years,  and  at  the  present 
time,  now  that  reversing  devices  are  constructed  as  a  part  of  the 
apron  mechanism,  the  feed  gears  may  be  placed  outside  of  the 
housing,  although  some  good  builders  still  keep  it  inside  and  con- 
nected in  practically  "the  same  old  way,"  even  if  the  "yoke  gears" 
or  reversing  gears  are  omitted. 


FIG.  58.  —  Another  Form  of  Strengthening  Brace. 

When  reversing  gears  were  thought  necessary  to  be  upon  the 
inside  of  the  housing,  a  hole  was  cut  out  for  them  in  the  raised 
arch  A,  Fig.  58,  and  this  practice  was  followed  in  any  head-stock 
having  this  or  a  similar  obstruction  to  these  gears,  and  provided, 
of  course,  that  they  were  to  be  located  inside  of  the  rear  housing. 

One  of  the  recent  modifications  of  the  above  form  is  that  shown 
in  Fig.  59,  which  is  a  type  of  the  Hendey-Norton  manufacture. 
The  central  figure  is  a  front  elevation  with  the  sectional  form  indi- 
cated by  dotted  lines.  The  figure  at  the  left  is  a  rear  end  elevation 
with  the  internal  form  on  the  line  A,  A,  of  the  central  figure,  while 
the  figure  on  the  right  is  a  similar  elevation  of  the  front  end  with 
dotted  lines  showing  the  section  on  the  line  B,  B. 

It  will  be  seen  that  the  portion  of  the  base  on  the  line  A,  A,  is  of 
arched  form,  somewhat  as  shown  at  A,  Fig.  58,  while  the  form  at 


98 


MODERN   LATHE   PRACTICE 


the  line  B,  B,  is  of  an  inverted  arch,  or  as  frequently  called  by  the 
shop  men  a  "pig  trough"  shape.  This  latter  form  enab'es  the 
metal  to  be  carried  higher  up  at  the  front  and  back  while  the  center 
is  depressed  to  give  proper  clearance  for  the  larger  steps  of  the  cone 
and  the  face  gear.  At  the  lowest  part  of  this  depression  there  is 
usually  an  opening  through  which  oil  may  drip  so  as  not  to  collect 
inconveniently  at  this  point.  The  arch-like  form  near  the  rear 
housing  adds  very  much  to  the  strength  and  rigidity  of  the  casting. 
It  will  be  noticed  that  in  this  design  the  main  spindle  boxes  are 
not  " capped  in,"  that  is,  held  down  by  removable  caps.  More 
will  be  said  of  this  peculiarity  in  describing  boxes  and  spindles. 

The  cores  beneath  the  base  are  carried  up  into  the  housings  in 
many  of  the  modern  head-stocks  as  far  as  possible,  and  still  leave 
ample  support  for  the  boxes  and  spindles.  The  advisability  of 


FIG.  59.  —  The  Hendey-Norton'Form  of  Head-Stock. 

this  method  of  lightening  the  weight  of  the  casting  is  still  an  open 
question  among  machine  tool  designers  who  have  endeavored  to 
avoid  unequal  strains  in  the  shrinkage  of  castings  by  making  all 
members  of  as  nearly  equal  thickness  as  possible.  Sometimes  this 
idea  is  carried  too  far  and  the  result  is  liable  to  be  that  of  sacrificing 
the  necessary  rigidity  to  prevent  vibration,  in  the  effort  to  follow 
out  the  ideal  as  to  strains. 

Fig.  60  shows  a  head-stock  in  which  the  inverted  arch  form  is 
continued  the  entire  length  between  the  housings,  but  is  carried 
upon  a  curved  line  as  shown  and  forms  a  very  graceful  curve.  The 
three  figures  are  arranged  the  same  as  those  comprising  Fig.  59. 
The  height  of  the  curve  might  be  greater  at  the  line  A,  A,  as  will 
be  shown  in  some  others  further  on  in  this  chapter,  and  the  strength 
of  the  casting  considerably  increased. 


LATHE  DESIGN:  THE  HEAD-STOCK  CASTING,   ETC.       99 

This  form  is  used  with  few  modifications  to  adapt  it  to  the  diam- 
eters of  driving-cones,  the  nature  of  the  back  gears  and  the  feed 
gears  and  similar  conditions  that  tend  to  somewhat  alter  the 
construction  outlines  of  its  design.  This  form  seems  to  be  a  favorite 
one  with  designers,  since  among  all  the  different  builders  and 
the  variety  of  designs  there  are  more  builders  using  this  form 
than  all  the  others  put  together. 


FIG.  60.  —  Form  of  Head-Stock  built  by  a  Majority  of  Lathe  Builders. 

While  the  above  form  of  design  carries  a  reversed  curve  for  the 
top  of  the  base,  the  form  used  by  Shumacher  and  Boye,  shown 
in  Fig.  61,  is  of  a  single  curve  from  rear  to  front  housing  and  the 
inverted  arch  in  its  transverse  sectional  form.  In  this  design  the 
front  and  back  is  carried  high  up  near  the  rear  housing  and  com- 
paratively low  down  near  the  front  housing. 


FIG.  61.  —  The  Schumacher  &  Boyce  Form  of  Head-Stock. 

This  is  a  design  of  much  strength  and  rigidity  in  proportion  to 
the  weight  of  the  casting,  the  metal  being  well  distributed  to  resist 
heavy  strains  in  the  operation  of  the  lathe. 

The  Le  Blond  type  is  shown  in  Fig.  62.  In  this  we  have  a 
straight  line  at  the  back  and  front,  with  a  modification  of  the  re- 
versed curve  and  the  combination  of  the  arch  proper  and  the  in- 
verted arch  as  shown  in  Fig.  59.  The  form  is  pleasing  to  the  eye, 


100 


MODERN  LATHE  PRACTICE 


and  the  strength  of  the  casting  is  quite  sufficient  for  the  require- 
ments. In  this  case  the  housings  are  made  of  ample  width, 
especially  the  front  one.  They  are  cored  out  inside  so  as  to 
have  substantially  an  equal  thickness  of  metal  at  nearly  all  parts. 
The  New  Haven  type  of  head-stock  is  shown  in  Fig.  63.  In 


FIG.  62.  —  The  Le  Blond  Form  of  Head-Stock. 

this  case  the  inverted  arch  is  used  all  the  way  through,  but  it  is 
upon  straight  lines,  that  form  a  cross  section  at  A,  A,  continuing 
straight  and  on  a  proper  incline  to  a  point  near  the  line  B,  B,  from 
whence  it  is  horizontal. 

This  design  gives  great  strength,  and  with  the  proper  propor- 
tions and  thickness  of  metal  throughout  it  is  as  rigid  as  it  is  possible 
to  design  a  head-stock.  The  housings  are  unusually  thick  and  cored 
out  underneath  as  shown  by  dotted  lines. 

The  design  shown  in  Fig.  64  is  by  Hendey-Norton,  and  is  prac- 


FIG.  63.  —  The  New  Haven  Form  of  Head-Stock. 

tically  the  same  as  that  shown  in  Fig.  59,  except  for  the  arched 
brace  C,  from  the  front  to  the  rear  housing,  effectually  tying 
them  together  and  thus  adding  considerably  to  the  rigidity  of  the 
spindle-bearing  boxes,  which  is  always  an  excellent  point  to  be 
considered. 

The  fact  that  these  housings  are  solid,  that  is,  not  held  by  separ- 
ate caps,  permits  the  addition  of  this  very  strong  brace,  which  could 


LATHE  DESIGN:  THE  HEAD-STOCK  CASTING,   ETC.     101 

not  be  efficiently  added  to  a  head-stock  whose  boxes  are  held  in  by 
a  separate  cap. 

While  this  idea  is  now  quite  common  in  the  design  of  milling 
machines,  it  has  not  been  applied  to  the  head-stocks  of  lathes  by 
any  builders  but  these  so  far  as  is  known. 

There  are  many  classes  of  work  in  which  a  head-stock  so  braced 
would  be  very  valuable,  as  its  strength  and  rigidity  is  much  increased 
by  it  and  the  strain  and  vibration  is  considerably  reduced,  which 
has  the  effect  of  increasing  the  efficiency  and  also  the  life  of  the 
cutting-tools.  This  question  of  increased  rigidity  and  the  impor- 
tance of  obtaining  it  has  received  much  attention  in  the  past  few 
years,  and  the  result  has  been  the  constant  increase  in  the  pro- 


A 

FIG.  64.  —  Special  Form  of  Hendey-Norton  Head-Stock. 

portions  and  the  weights  of  all  parts  of  metal-working  machinery 
which  form  the  supports  of  cutting-tools  or  their  intermediary 
parts.  It  is  altogether  probable  that  in  this  increase  in  weight  the 
limit  has  not  been  reached,  but  that  it  will  continue  in  years  to 
come,  although  not  perhaps  in  the  same  proportion  that  it  has  dur- 
ing the  last  decade.  The  use  of  high-speed  steel  will,  doubtless, 
be  extended  to  other  uses  than  at  present,  and  its  price  will  be 
materially  reduced,  thus  increasing  the  amount  used  and  conse- 
quently demanding  stronger  machines  and  more  power  to  drive 
them,  so  as  to  continually  reduce  the  cost  of  the  product  by  reduc- 
ing the  time  of  machine  operations. 

Having  designed  a  good  head-stock  with  ample  proportions  in 
general,  the  metal  so  distributed  as  to  withstand  not  only  the 
strains  to  which  it  will  be  subjected  in  performing  its  appointed 


102 


MODERN   LATHE   PRACTICE 


functions,  but  with  proper  considerations  for  the  changes  which 
will  take  place  in  the  process  of  casting  and  cooling,  and  not  for- 
getting that  castings  will  change  their  form  more  or  less  for  weeks 
after  being  cast,  our  next  concern  will  be  the  spindle. 

It  is  not  enough  to  say,  as  catalogues  sometimes  do,  that  "the 
spindle  is  of  hammered  crucible  steel  of  large  diameter  and  runs 
in  hard  bronze  boxes."  This  may  all  be  relatively  true  and  yet  it 
may  be  neither  properly  designed  or  properly  constructed  for  the 
uses  to  which  it  is  to  be  put. 

To  design  a  lathe  spindle  we  must  consider  the  work  it  has  to  do, 
the  points  at  which  it  will  be  supported,  the  points  where  it  must 
support  the  material  that  is  to  be  machined,  and  the  parts  with 


FIG.  65.  —  Lathe  Spindle  showing  Principal  Weight  on 
Front  Bearing. 

which  it  is  loaded  and  which  become  a  part  of  its  attendant  mech- 
anism ;  not  only  these  points,  but  others  that  are  equally  important,— 
the  torsional  strains  to  which  it  will  be  subjected  in  performing  its 
regular  functions,  and  which  include  that  of  driving  the  piece 
to  be  turned,  of  the  strains  of  the  cone  when  driving  direct,  or 
the  back  gears  or  triple  gears  when  they  are  in  action,  and  of  the 
feeding  mechanism  which  derives  its  motion  from  the  rear  end  of 
the  spindle. 

If  we  are  to  consider  principally  the  weight  of  the  face-plate 
and  the  material  to  be  turned,  which  falls  almost  entirely  upon  the 
front  journal,  we  should  have  the  form  of  the  lathe  spindle  as  repre- 
sented in  Fig.  65.  In  this  case  the  front  bearing  would  necessarily 
be  very  large  and  strong  and  with  ample  support.  The  rear  bear- 
ing need  not  be  a  matter  of  serious  consideration,  as  it  is  quite  a 


LATHE  DESIGN:  THE   HEAD-STOCK  CASTING,   ETC.     103 


distance  from  the  front  bearing,  while  the  weight  of  the  face-plate 
or  chuck  carrying  the  work,  or  the  center  which  supports  one  end 
of  the  work,  if  supported  by  this  means,  carries  nearly  all  the  strain. 
Therefore  the  rear  bearing  may  be  small  and  short  as  shown. 

Again,  if  the  weight  of  the  cone  and  its  parts  are  to  be  prin- 
cipally considered,  we  should  have  a  spindle  more  nearly  conform- 
ing to  the  outline  shown  in  Fig.  66,  the  rear  bearing  being  larger 
and  the  front  bearing  smaller  than  is  shown  in  Fig.  65.  This  would 
also  be  the  case  if  the  upward  pull  of  the  belt  were  a  governing 
factor  in  determining  the  form  and  proportion  of  the  spindle.  But 
the  fact  is  that  the  cone  and  its  action  upon  the  spindle,  so  far  as 
its  weight  or  the  belt  pull  upon  the  spindle,  while  in  reality  a  factor 


-B  £- 


FIG.  66.  —  Form  of  Lathe  Spindle  when  undue  prominence 
is  given  to  Cone  Pulley. 

to  be  considered,  as  will  be  referred  to  later  on,  is  not  the  prime 
factor  by  any  means.  Therefore  we  must  recur  to  the  form  shown 
in  Fig.  65  for  the  points  necessary  for  the  proper  consideration  of 
forms,  the  determination  of  the  contour,  and  the  proper  propor- 
tions of  the  lathe  spindle. 

This  view  of  the  case  leads  us  to  the  choice  of  a  medium  between 
the  two  extremes  presented  and  an  ideal  form  as  shown  in  Fig.  67, 
wherein  the  conditions  governing  both  the  former  examples  are 
properly  considered  and  met. 

There  is  one  more  condition  to  be  considered,  however.  This 
is  the  upward  or  lifting  tendency  supposed  to  exist  by  reason  of  the 
cutting-tool  forming  a  fulcrum,  which,  in  connection  with  the  cir- 
cular motion  of  the  piece  being  turned,  tends  to  lift  the  spindle  in 
the  front  box  and  so  throws  an  upward  strain  on  the  cap  over  the 


104 


MODERN  LATHE  PRACTICE 


front  journal.  This  tendency  is  represented  in  Fig.  68,  wherein 
the  arrow  shows  the  direction  of  the  belt  and  revolution  of  the 
material  being  turned.  It  is  doubtful,  however,  if  this  point  is  of 
much  importance,  particularly  in  a  lathe  properly  designed  as  to 
the  dimensions  and  weights  of  its  parts,  especially  of  the  spindle 
and  its  appendages. 


FIG.  67.  —  Ideal  Form  of  Lathe  Spindle. 

Taking  all  these  matters  into  consideration  we  shall  find  that 
the  proper  proportion  and  design  of  the  spindle  with  the  face  gear, 
cone  pinion,  and  the  feed  gear,  will  be  substantially  as  shown  in 
Fig.  68,  leaving  out  of  the  design  for  the  time  being  the  special 


FIG.  68.  —  The  Ideal  Spindle  shown  in  Practical  Form. 

form  of  journal  oiling  devices,  the  thrust  bearing  for  the  rear  end 
and  the  special  form  of  the  nose  of  the  spindle,  which  will  next 
receive  attention. 

As  to  the  nose  of  the  spindle.     It  is  customary  by  many  builders 
to  cut  the  thread  on  the  nose  of  the  spindle  nearly  up  to  the  collar, 


LATHE  DESIGN:  THE  HEAD-STOCK  CASTING,  ETC.     105 

against  which  the  chuck-plate  or  the  face-plate  takes  its  bearing. 
It  is  a  well-known  fact  that  it  is  extremely  difficult  to  accurately 
center  such  a  plate  upon  a  threaded  portion  of  a  spindle.  As  the 
purpose  of  the  thread  is  simply  to  prevent  the  plate  from  coming 
off  the  spindle,  it  naturally  follows  that  the  length  of  this  thread 
may  be  very  much  reduced  without  in  any  way  reducing  its  capac- 
ity to  securely  hold  the  plate  in  place.  It  is  also  quite  as  evident 
that  we  can  hold  the  plate  perfectly  true  in  its  place  and  exactly 
concentric  with  the  front  bearing  if  we  grind  a  portion  of  the  nose 
of  the  spindle  to  a  truly  cylindrical  form  when  we  grind  the  front 
bearing  and  then  fit  a  sufficient  portion  of  the  bore  in  the  plate  to 
this  ground  surface.  This  may  be  accomplished  by  threading  the 
nose  of  the  spindle  through  only  one  third  of  its  length,  and  grind- 
ing the  remaining  two  thirds  to  which  the  chuck-plate  or  face-plate  is 
fitted.  This  centers  the  plate  accurately  with  the  axis  of  the  spindle. 
If  the  face  of  the  collar  is  accurately  ground,  and  the  hub  of  the 
chuck-plate  or  face-plate  fits  fairly  against  it,  there  will  be  no  diffi- 
culty when  removing  the  plate  of  always  being  able  to  replace  it  in 
exactly  its  former  position,  perfectly  true  in  the  running  of  its  face 
and  perfectly  concentric  with  the  ground  bearings  of  the  spindle. 
Even  the  wearing  of  the  thread  will  not  effect  its  true  running, 
since  the  only  office  of  the  thread  is  to  hold  it  on,  while  the  ground 
surfaces  insure  its  trueness.  This  is 
shown  in  Fig.  69. 

In  this  connection  it  is  noticeable, 
that  some  manufactures  omit  the  large 
collar  on  the  front  end  of  the  spindle 
and  furnish  only  a  small  shoulder  on 
the  spindle,  due  to  the  nose  being  some-  FlG'  69'  ~  Nose  of  sPindle' 
what  smaller  than  the  front  bearing,  against  which  the  face-plate 
or  chuck-plate  rests,  and  assuming  that  its  close  fit  upon  the  ground 
surface  between  this  shoulder  and  the  threaded  portion  will  be 
quite  sufficient  for  all  purposes.  This  would  seem  to  be  an  errone- 
ous view  of  the  question  as  this  comparatively  small  shoulder  can- 
not possibly  afford  the  support  and  rigidity  that  may  be  obtained 
by  a  collar  or  thrust  surface  of  two  or  three  times  the  area.  It  is 
true  that  as  a  matter  of  economy  in  furnishing  the  stock  for  these 
spindles  the  question  favors  the  omission  of  the  shoulder.  But 


106  MODERN   LATHE   PRACTICE 

as  a  matter  of  good  design  and  proper  shop  practice  it  will  hardly 
be  disputed  that  the  larger  collar,  forged  on,  is  the  proper  design 
and  construction. 

Referring  again  to  Fig.  68,  there  are  several  points  to  which  it  is 
proper  to  call  attention.  The  spindle  boxes  represented  are  of 
bronze  and  such  as  are  now  commonly  used  in  good  lathes.  The 
formation  of  the  front  end  of  the  spindle  with  its  fixed  collar  formed 
in  the  forging  is  also  the  usual  practice,  except  in  some  of  the  lathes 
of  newest  design  and  development,  in  which  it  is  probably  omitted 
as  being  considered  an  unnecessary  expense.  The  thrust  bearing 
is  similar  to  that  represented  in  Fig.  74,  but  an  improvement  upon 
it,  since  a  hardened  steel  ring  is  interposed  between  two  bronze 
rings,  which  render  cutting  well-nigh  impossible. 

The  cone  pinion  is  made  of  machine  steel  and  has  a  long  sleeve 
forced  into  the  small  end  of  the  spindle  cone.  While  it  is  not  good 
practice  to  run  two  steel  surfaces  together  unless  one  is  hardened, 
it  is  still  perfectly  practicable  in  this  case  as  the  pinion  is  of  ordinary 
soft  machine  steel  while  the  spindle  is  50  to  60-point  carbon  crucible 
steel,  which  answers  the  conditions  in  practice  and  many  lathes  are 
now  built  in  this  manner. 

The  spindle  is  shown  bored  out,  as  a  large  majority  of  lathes  are 
now  so  constructed  and  the  demands  of  the  customers  require 
hollow  spindles  in  nearly  every  instance  when  the  lathe  is  over 
12-inch  swing. 

The  proportions  upon  which  this  design  is  made  may  be  inter- 
esting. Using  the  full  swing  of  the  lathe  in  inches  as  a  unit,  repre- 
sented by  A,  the  proportions  of  the  spindle  will  be  as  follows: 

Diameter  of  the  front  bearing,  A  -f-  5.7" 

Length  of  the  front  bearing,  A  -j-  3.6" 

Diameter  of  the  rear  bearing,  A  -=-  6" 

Length  of  the  rear  bearing,  A  -=-  4.5" 

Length   of   the   nose   of   the   spindle,  A  -r-  6" 

Distance  between  bearings,  A  X  1.2" 

Diameter  of  bore  through  spindle,  A  -=-  10" 

In  Fig.  70  we  have  a  spindle  of  somewhat  overgrown  propor- 
tions, yet  one  of  proportions  advocated  by  an  eminently  practical 
mechanic  who  is  said  to  have  remarked  that  he  "  didn't  want  a 
lathe  spindle  with  a  front  bearing  so  many  inches  diameter  and  so 


LATHE  DESIGN:  THE   HEAD-STOCK  CASTING,   ETC.     107 


many  inches  long,  but  he  wanted  it  with  a  bearing  so  many  inches 
large  and  so  many  inches  short,"  by  which  we  may  readily  under- 
stand his  idea  that  a  large  and  short  front  bearing  was  much  better 
adapted  to  the  work  than  one  of  medium  diameter  and  extra 
length. 

Thus  if  we  have  a  front  bearing  of  3J  inches  diameter  and  5 
inches  long,  and  we  increase  the  diameter  50  per  cent  and  reduce 
the  length  in  the  same  proportion,  viz.,  one  third,  we  shall  have  about 
the  same  area  of  bearing  surface,  but  we  shall  gain  the  advantage 
of  bringing  the  driving-cone  closer  to  the  work,  of  shortening  the 
whole  length  of  the  spindle,  and  of  making  the  front  end  of  the 
spindle  much  more  rigid  and  better  adapted  to  withstand 
the  strain  of  a  heavy  cut  on  work  of  the  usual  diameters,  and  still 


FIG.  70.  —  Lathe  Spindle  with  Extra  Large  Bearings. 

better  when  large  facing  work  is  to  be  done  and  the  cut  is  carried 

I  out  near  the  periphery  of  the  largest  diameter  that  can  be  handled. 
It  does  not  follow,  however,  that  the  proportions  of  the  en- 
larged diameter  of  the  front  bearing  need  be  carried  all  the  way 
through,  by  which  a  spindle  of  unnecessary  weight  would  be  pro- 
duced, as  practically  all  important  advantages  may  be  gained  if  its 
dimensions  are  as  shown  in  dotted  lines  in  the  engraving. 

In  Fig.  71  is  shown  the  opposite  method  of  designing  a  lathe 
spindle,  that  is,  by  making  the  bearings  of  the  usual  diameter,  but 
increasing  the  length  to  a  considerable  extent.  It  is  evident  that 
while  there  are  always  certain  advantages  in  increasing  the  dis- 
tance between  the  supporting  boxes,  there  is  an  apparent  tendency 
to  weakness,  or  lack  of  rigidity  of  the  spindle  at  the  vital  poiot. 
namely,  the  overhanging  portion  of  the  front  end  of  the  spindle 


108 


MODERN   LATHE   PRACTICE 


which  supports  the  face-plate,  the  chuck,  or  the  work  as  it  bears 
upon  the  lathe  center. 

As  between  the  two  designs  of  extra  large  bearings  and  extra 
long  bearings,  the  practical  advantages  seem  to  be  in  favor  of  the 
former. 


D 


FIG.  71.  —  Lathe  Spindle  with  Extra  Long  Bearings. 

The  spindle  cone  should  receive  due  attention.  The  method 
of  introducing  the  cone  gear  sleeve  into  the  small  end  of  the  cone 
has  been  referred  to  in  connection  with  Fig.  68.  The  large  end-ef 
the  cone  may  have  an  inwardly  projecting  flange  cast  integral  with 
it  or  made  separate  and  attached  by  screws.  In  either  case  the 
locking  bolt  must  be  accommodated  in  it.  Between  this  head  and 
its  bearing  it  should  be  well  supported  from  the  central  quill.  This 
may  be  done  by  providing  for  four  or  more  radial  plates  extending 
from  the  connection  with  the  central  quill  under  the  smallest  step 
to  one  half  the  remaining  distance  toward  the  large  end  of  the 
cone,  as  shown  in  Fig.  68. 


FIG.  72.  —  Form  of  Cone  Steps. 

In  finishing  the  outside  of  the  cone  the  rising  steps  should  be 

faced  up  as  shown  in  Fig.  72,  that  is,  with  the  face  cut  back  from 

to  a6  of  an  inch,  according  to  the  size  of  the  cone,  for  the  pur- 


LATHE  DESIGN:  THE  HEAD-STOCK  CASTING,   ETC.     109 

pose  of  lessening  the  friction  on  the  edge  of  the  belt.  In  cases 
where  this  relief  is  not  given  to  the  belt  it  is  not  an  unusual  con- 
dition to  find  the  edges  of  belts  running  over  cones,  particularly  at 
high  speeds,  to  be  turned  up,  the  corners  where  the  belt  is  joined  to 
be  distorted  or  worn  away,  and  in  a  short  time  the  belt  well-nigh 
ruined. 

In  purchasing  lathes  or  other  machines  provided  with  speed 
cones,  the  purchaser  should  insist  that  the  faces  of  the  cones  should 
be  made  as  shown,  as  it  is  a  matter  of  much  importance  in  belt 
economy  and  belt  efficiency. 


CHAPTER  VI 

LATHE  DESIGN  :  THE  SPINDLE  BEARINGS,  THE  BACK  GEARS,  AND  THE 
TRIPLE   GEAR    MECHANISM 

Designing  spindle  bearings  and  boxes.  Thrust  bearings.  The  Lodge  & 
Shipley  form.  Ball  bearings.  Proper  metal  for  boxes.  The  cast  iron 
box.  Early  form  of  boxes.  The  cylindrical  form.  Thrust  bearings  for 
a  light  lathe.  Experiments  with  different  metals  on  high  speeds.  Curved 
journals.  The  involute  curve.  The  Schiele  curve.  Conical  bearings. 
Adjustments  to  take  up  wear.  Split  boxes.  Line-reaming  boxes.  Lu- 
brication of  spindle  bearings.  The  plain  brass  oil  cup.  The  use  of  a 
wick.  Oil  reservoirs.  Loose  ring  oilers.  Chain  oilers.  Lodge  & 
Shipley  oil  rings.  Neglect  of  proper  lubrication.  Back  gearing.  Vary- 
ing the  spindle  speeds.  Triple  gearing.  Theory  of  back  gearing.  Back 
gear  calculations.  Triple  gear  calculations.  Diagram  of  spindle  speeds. 
Faulty  designing  of  back  gears  and  triple  gears.  Four  examples.  A  14- 
inch  swing  lathe.  A  19-inch  swing  lathe.  A  17-inch  swing  lathe.  A 
30-inch  swing  triple-geared  lathe.  Explanation  of  the  back  gear  dia- 
grams. Essential  parts  of  the  triple  gear  mechanism.  "Guesswork" 
in  lathe  designing.  Wasted  opportunities.  Designing  the  head-stock. 
Cone  diameters.  A  homely  proportion.  The  modern  tendency  in  cone 
design.  Proportions  of  back  gears.  Driving  the  feeding  mechanism. 
Reversing  the  feed.  Variable  feed  devices.  Rapid  change  gear  devices. 

GREAT  care  ought  always  to  be  used  in  the  design  of  the  bearings 
of  the  spindle  and  the  boxes  in  which  they  run.  To  a  great  extent 
these  determine  the  life  and  usefulness  of  the  lathe,  for  with  an 
improperly  made  spindle  or  poor  boxes,  either  of  design  or  quality 
of  material,  the  lathe  is  soon  worn  so  much  out  of  true  as  to  bejDrac- 
tically  worthless. 

Mention  has  been  made  of  the  thrust  bearing  at  the  rear  box. 
It  is  important  that  this  should  be  well  designed  and  constructed, 
as  the  quality  of  the  lathe's  work,  particularly  face-plate  and  chuck 
work,  depends  upon  its  proper  performance. 

One  form  is  shown  in  Fig.  73,  which  is  a  style  used  for  a  number 

no 


LATHE   DESIGN:  THE  SPINDLE   BEARINGS,   ETC.        Ill 


of  years  on  the  New  Haven  lathes.  It  consists  of  a  hardened  steel 
ring  B,  forced  into  an  annular  groove  in  the  end  of  the  hollow 
spindle  A.  The  rear  end  of  the  bronze  box  C  is  extended  as  shown 
and  tapped  out  with  a  fine  thread.  Fitted  to  this  is  the  thrust 
sleeve  D,  whose  forward  end  bears  against  the  ring  B.  The  sleeve 
D  is  adjusted  by  means  of  two  slots  (one  of  which  is  shown)  cut 
across  its  face,  and  is  held  in  position  by  the  check-nut  E.  This 
device  is  much  improved  by  the  addition  of  a  hard  bronze  ring, 
loosely  interposed  between  the  thrust  sleeve  D  and  the  hardened 
ring  B.  The  sleeve  D  was  made  of  a  steel  casting,  as  was  also  the 
check-nut  E,  which  had  holes  drilled  around  its  circumference  for 
the  accommodation  of  a  spanner  for  adjusting  it.  The  device  was 
very  successful  in  practical  use. 


FIG.  73.  —  New  Haven  Lathe 
Thrust  Bearing. 


FIG.  74.  —  Lodge  &  Shipley 
Thrust  Bearing. 


The  form  of  thrust  bearing  used  on  the  Lodge  &  Shipley  lathes 
is  shown  in  Fig.  74,  and  is  constructed  as  follows :  Upon  the  spindle 
A  is  keyed  the  cast  iron  ring  B.  Next  to  this  is  a  bronze  washer  C; 
next  a  hardened  steel  washer  D;  then  another  bronze  washer  E, 
which  in  turn  rests  against  the  faced  end  of  the  rear  box  F,  which  in 
this  case  is  formed  of  the  head-stock  casting  itself. 

While  this  is  an  efficient  form  of  end  thrust  it  has  the  disadvan- 
tage of  occupying  some  space  inside  the  rear  box  and  consequently 
increasing  the  distance  between  the  front  and  rear  boxes,  increasing 
the  length  of  the  head-stock  by  just  its  own  width,  or  the  space 
occupied  by  the  cast  iron  collar  and  the  three  friction  washers. 
Unless  covered  by  a  projecting  portion  of  the  casting,  or  by  a 
special  guard  over  it,  there  will  be  more  or  less  trouble  on  account 
of  dirt  working  in  between  the  washers.  This,  however,  is  easy 
to  prevent  by  a  proper  design  and  construction. 


112  MODERN   LATHE  PRACTICE 

The  popularity  of  the  ball  bearing  and  its  successful  application 
to  many  different  uses  no  doubt  suggested  it  as  a  proper  device  for 
the  thrust  bearing  of  a  lathe.  It  has  been  objected  to  in  a  lathe 
designed  for  fine  work,  on  account  of  the  possible  influence  of  any 
slight  vibration  caused  by  the  rapid  rotation  of  the  balls,  owing  to 
any  inaccuracy  in  their  perfect  spherical  shape  or  diameters.  Yet 
the  device  is  in  apparently  successful  use  on  many  lathes  at  this 
time.  The  construction  is  shown  in  Fig.  75.  Upon  the  spindle  A 

is  fixed  the  collar  B,  having  a  ball- 
race  cut  in  its  rear  side  as  shown. 
Fixed  to  the  end  of  the  box,  or  the 
inside  of  the  rear  housing,  as  the 
case  may  be,  is  the  collar  C,  which  also 
has  a  ball-race  formed  in  it,  and  set 
deep  enough  to  form  a  sleeve  which 

projects  out  over  the  balls  and  the 
FIG.  75.  —  Ball  Thrust  Bearing.  •   r     J 

collar  B,  so  as  to  protect  the  balls 

from  dirt.  This  thrust  is  open  to  one  of  the  objections  urged 
against  the  form  shown  in  Fig.  74,  namely,  the  space  it  occupies  on 
the  lathe  spindle. 

It  is  entirely  feasible,  however,  to  place  this  device,  or  the  one 
shown  in  Fig.  74,  near  the  rear  end,  or  even  at  the  center  of  the  rear 
box  if  so  desired.  In  this  location  it  would  have  the  added  advan- 
tage of  position  for  ample  lubrication  and  absolute  protection  from 
dirt. 

There  has  been  a  great  deal  of  discussion  on  the  question  of 
what  is  the  proper  metal,  and  what  is  the  proper  form  for  a  lathe 
spindle  box.  Any  number  of  different  metals  have  been  used  for 
this  purpose,  from  cast  iron  at  a  cost  of  two  and  one  half  cents  per 
pound  to  a  fine  quality  of  nickel-bronze  worth  thirty  one  cents 
per  pound. 

It  is  an  old  and  a  true  saying  that  with  a  good,  true,  and  well 
finished  journal,  and  the  bearing  kept  free  from  dirt,  always  clean 
and  well  lubricated  with  good  oil,  a  cast  iron  box  is  as  good  as 
anything  that  can  be  made.  Every  practical  shop  man  of  even 
moderate  experience  can  cite  instances  of  the  excellent  record  of 
the  old-time  cast  iron  box,  and  the  fact  that  it  is  still  used  by  some 
of  the  oldest  and  best  lathe  manufacturers  is  certainly  a  strong 


LATHE  DESIGN:  THE  SPINDLE  BEARINGS,   ETC.        113 

argument  in  its  favor.  But  one  condition  is  always  insisted  upon : 
it  must  be  kept  clean  and  free  from  dirt.  It  will  not  stand  dirt. 
Under  adverse  conditions  many  bronze  boxes  withstand  success- 
fully dirt,  grit,  and  poor  lubrication  that  would  put  the  cast  iron 
box  out  of  business  in  a  few  hours. 

Of  course  it  is  assumed  in  all  these  remarks  that  the  lathe 
spindles  are  made  of  50  to  60-point  crucible  steel,  and  that  they 
have  been  accurately  ground,  as  this  is  the  only  method  by  which 
we  can  insure  the  perfect  cylindrical  form  of  the  bearing  that  is  so 
necessary  to  the  successful  operation  of  a  lathe. 

The  older  form  of  designing  the  housing  of  the  head-stock  for 
the  reception  of  the  boxes  was  to  have  the  opening  at  the  head  and 
rear  end  of  square  form  and  covered  by  a  straight  bar  of  cast  iron 
or  machine  steel,  secured  at  the  ends  by  hexagonal  headed  cap 
screws.  Later  on  it  was  found  more  economical  to  make  these 
spaces  circular  and  to  have  them  bored  out  with  a  boring  bar,  the 
boxes  being  fitted  to  the  circular  opening  and  capped  down,  when 
the  inner  surface  of  the  box  itself  was  bored  out  and  hand  reamed. 

For  small  lathes,  such  as  bench  lathes  and  precision  lathes,  it  is 
necessary  to  carefully  exclude  dirt  as  well  as  to  have  correct 
bearings,  since  a  good,  true  bearing  will  not  long  remain  so  if  ex- 
posed to  dust  and  dirt  or  even  to  poor  and  dirty  oil  used  as  a  lubri- 
cant. 

In  Fig.  76  is  shown  a  thrust  bearing  for  a  light  lathe  that  is  pro- 
vided   with   an   adjustment    on 
both  the  front  and  the  rear  side 
of    the   rear   housing.      This   is 
done  by  providing  the  steel  col- 
lars B,  B,    threaded  to  fit  the 
spindle  A,  so  as  to  allow  adjust- 
ment at  either  end,  and  that  one 
of  these  collars  at  each  end  shall          FlG"  76  s~a^eLat^eearing  for 
act  as  a  check-nut  to  the  other, 

while  the  wear  is  taken  by  the  loose  bronze  collars  C,  C,  interposed 
between  the  steel  collars  and  the  face  of  the  housing. 

The  faced  sides  of  the  housing  project  to  the  front  and  rear  a 
short  distance,  and  this  projecting  part  is  threaded  and  has  fitted 
to  it  the  dust-caps  D,  D,  which  may  be  made  of  steel,  as  shown, 


114 


MODERN   LATHE   PRACTICE 


but  are  frequently  made  of  brass.  They  are  bored  to  fit  the  spindle 
rather  closely  so  as  to  more  effectually  exclude  dirt.  In  some  in- 
stances it  may  be  advisable  to  place  outside  of  the  outer  collar  B 
a  felt  washer  closely  fitting  the  spindle,  which  will  be  an  effectual 
means  of  insuring  a  clean  bearing. 

If  the  thrust  on  the  spindle  is  considerable,  it  may  be  well  to 
interpose  two  washers  so  as  to  decrease  the  friction,  and  for  still 
heavier  thrusts  we  have  always  recourse  to  the  plan  of  using  a  steel 
washer  with  a  bronze  one  on  each  side  of  it,  which  will  in  nearly 
every  case  be  found  sufficient  even  with  a  very  heavy  end  pressure. 
In  the  case  given  in  Fig.  76,  it  will  be  noticed  that  the  spindle  runs 
in  a  reamed  hole  in  the  cast  iron  of  the  head-stock  itself.  This 
has  been  so  arranged  purposely  and  forms  a  very  good  bearing 
when  carefully  protected  from  dirt.  Such  bearings  may,  of  course, 
be  lined  with  genuine  babbitt  metal  or  with  brass,  bronze,  or  any 
of  the  so-called  "  anti-friction  metals." 

In  an  extended  series  of  experiments,  the  purpose  of  which 
was  to  ascertain  the  best  materials  for  a  shaft  and  a  box  running 
at  high  speeds,  in  this  case  7000  to  8000  revolutions  per  minute,  it 
was  demonstrated  that  a  hardened  and  ground  tool  steel  spindle, 
running  in  a  box  of  cast  tin,  bored,  reamed,  and  scraped,  would 
far  outlast  any  of  the  dozen  or  more  materials  tested.  The  inner 
surface  of  the  box  soon  took  on  a  glaze  that  was  nearly  black  and 
very  glossy,  and  this  was  retained  during  over  a  year's  wear  to  the 
author's  personal  knowledge,  and  probably  much  longer.  In  this 
series  of  experiments  a  steel  shaft  and  steel  box  was  ruined  in  less 
than  an  hour's  run. 

Hitherto  attention  has  been 
directed  to  straight  or  cylindri- 
cal bearings,  that  is,  those  of 
the  same  diameter  at  both 
ends.  Where  a  very  accurate 
bearing  is  required,  and  one 
that  will  stand  a  great  amount 
of  wear  and  still  maintain  its 

correct  alignment,  the  involute 
FIG.  77.  —  Involute  Front  Bearing.          ,         .         <*  -n.      f-n  .     ,-, 

bearing  shown  in  Fig.  77  is  the 

proper  form.    About  one  half  the  length  of  this  bearing  may  be  a 


LATHE  DESIGN:  THE  SPINDLE   BEARINGS,   ETC.        115 


straight  line,  but  conical,  inclined  two  degrees  from  the  axis.  The 
remainder  of  the  length  has  either  an  involute  or  elliptic  form  to  a 
diameter  60  per  cent  larger  than  the  small  end  of  the  bearing.  The 
involute  form  is  preferable,  while  the  "Schiele  curve"  is,  of  course, 
the  ideal  contour.  The  spindle  is  held  in  place  by  the  collars  B,  B, 
threaded  upon  the  spindle  A,  and  a  bronze  washer  C,  interposed  to 
eliminate  friction.  While  this  is  theoretically  correct  and  entirely 
practicable,  it  is  an  expensive  bearing  to  make  and  to  fit  up  in 
small  numbers,  and  when  special  tools  are  made  for  it  they  are  ex- 
pensive to  maintain. 

For  these  reasons  there  was  designed  a  sort  of  compromise 
form  which  is  shown  in  Fig.  78, 
and  which  is  not  subject  to 
the  disadvantages  referred  to 
above.  The  conical  portion 
has  an  inclination  of  three  de- 
grees with  the  axis,  and  the 
angle  at  the  large  end  is  twenty 
degrees  from  a  right  angle  with 
the  axis.  In  practice  it  is  much 
more  economically  made  and  FlG-  78-  —  Conical  Front  Bearing, 
fitted  and  answers  all  conditions  nearly  as  well. 

The  arrangements  for  taking  up  wear  are  the  same  as  those 
shown  in  Fig.  77.  In  neither  case  is  a  thrust  bearing  required  at 
the  rear  box.  In  some  respects,  particularly  in  small  lathes,  this 
is  considered  the  better  practice. 

In  Fig.  79  is  shown 
another  form  of  adjustable 
bearing  which,  like  the  de- 
signs shown  in  Figs.  77  and 
78,  has  the  very  important 
advantage  of  always  main- 
taining the  correct  align- 
ment of  the  spindle.  One 
of  the  difficulties  of  all  spin- 

7Q  dies     running     in     "  split 

79. — Adjustable  Conical  Front  Bearing. 

boxes     is    that    the    lower 
half  of  the  box  wears  more  than  the  cap   and  consequently  the 


116  MODERN  LATHE  PRACTICE 

spindle  is  gradually  but  surely  wearing  lower.  This  is  corrected  by 
placing  pieces  of  paper  or  very  thin  metal  under  the  lower  box. 
But  as  sufficient  attention  is  seldom  given  to  this  point  in  keeping 
a  lathe  in  proper  condition,  it  is  most  unusual  to  find  a  lathe 
whose  centers  are  in  perfect  alignment. 

In  the  present  case  the  spindle  A  is  cylindrical,  that  is,  with  no 
taper,  and  runs  in  a  hard  bronze  sleeve  B,  which  has  a  taper  of  two 
degrees  on  each  side  and  fits  closely  in  the  taper  reamed  hole  in  the 
head-stock  housing.  This  bronze  sleeve  is  split  through  its  length 
and  arranged  to  be  drawn  into  the  taper  hole  by  means  of  two  nuts 
C,  C,  threaded  upon  its  small  end.  One  of  these  nuts  acts  as  a 
check-nut  to  the  other.  Therefore  the  bronze  sleeve  may  always 
be  drawn  as  tightly  around  the  spindle  bearing  as  may  be  desired, 
and  effectually  held  in  that  position.  As  the  compression  is  the 
same  through  the  entire  circumference,  the  spindle  will  retain  its 
central  position  and  correct  alignment  even  after  a  very  consider- 
able amount  of  wear,  and  a  new  bronze  sleeve  may  be  readily  fitted 
when  the  first  one  is  worn  out.  This  substitution  is  not  only 
economical  but  the  exact  alignment  is  still  preserved. 

It  may  be  argued  that  this  sleeve,  like  the  split  box,  will  wear 
most  at  the  bottom.  This  is  perfectly  correct,  but  an  occasional 
turning  of  the  sleeve  through  a  quarter  or  a  sixth  of  a  revolution, 
effectually  corrects  this  tendency. 

As  shown  in  Fig.  79,  this  bearing  is  protected  by  dust-caps  or 
rings  D,  D,  which  may  still  further  be  reinforced  by  the  introduc- 
tion of  felt  washers. 

However  these  bearings  are  made  and  whatever  care  may  be 
exercised  in  machining  and  fitting  the  boxes  or  in  securing  a  correct 
alignment  of  the  circular  or  square  receptacles  in  the  housings  for 
receiving  the  boxes,  it  will  be  found  generally  necessary  and  always 
safe  and  advisable  to  " line-ream"  the  boxes  after  they  are  in  place 
and  securely  clamped.  This  is  done  by  fixing  very  carefully  ground 
shell  reamers  upon  a  perfectly  true  arbor  or  mandrel,  and  hand 
reaming  both  boxes  at  the  same  time.  The  previous  diameters 
should  have  been  made  very  close  to  the  finished  dimensions  so  as 
to  leave  as  little  as  possible  to  ream  by  hand.  Really  the  cutting 
edges  of  the  reamer  should  barely  scrape  out  a  very  trifle  of  the 
metal.  In  fact,  it  should  be  rather  a  scraping  than  a  reaming  job, 


LATHE  DESIGN:  THE  SPINDLE  BEARINGS,   ETC.        117 


but  it  will  generally  be  found  in  practice  that  the  reamer  will  scrape 
a  little  harder  in  one  place  than  in  another,  showing  the  practical 
necessity  for  its  use. 

In  the  drawings  illustrating  the  different  forms  of  bearings  and 
spindles  the  devices  by  which  the  journals  are  lubricated  have  been 
omitted  so  as  not  to  confuse  the  question.  The  matter  of  lubrica- 
tion is,  however,  an  important  one,  and  will  next  claim  our  atten- 
tion. 

In  many  cases  the  spindle  bearings  are  lubricated  by  means  of 
a  simple  oil  hole  closed  by  a  plug  of  brass.  In  others  a  short  vertical 
tube  is  inserted  and  covered  by  a  cap  which  entirely  encloses  it. 
In  still  others  the  " plain  brass  oil  cup"  is  used,  that  is,  a  simple 
receptacle,  usually  urn-shaped,  whose  top  is  closed  by  a  cover 
screwing  into  it.  Again,  various  patented  devices  are  employed, 
ranging  all  the  way  through  "good,  bad,  and  indifferent,"  whose 
object  is  to  furnish  easy  access  to  the  oil  tube  and  to  provide,  in 
many  cases,  for  the  automatic  closing  of  the  oil  tube  or  reservoir 
for  the  purpose  of  excluding  dirt. 

An  improvement  upon  the  plain  brass  oil  cup  is  shown  in  Fig.  80. 
This  improvement  consists  in  the  intro- 
duction of  a  vertical  tube  A,  whose 
lower  end  opens  into  the  hole  leading 
to  the  journal  bearing.  This  tube  is 
fitted  with  a  wick  B,  whose  lowrer  end 
rests  upon  the  journal  C,  and  whose 
upper  end  is  coiled  loosely  about  in 
the  oil  chamber.  When  the  oil  in  the 
reservoir  is  above  the  top  of  the  tube 
the  wick  prevents  the  oil  from  run- 
ning down  too  rapidly.  When  the  oil 
is  below  the  top^of  the  tube  the  wick 
acts  as  a  siphon  and  thus  insures  the 
lubrication  of  the  bearing. 

The  use  of  a  wick  is  resorted  to  in  the  next  example,  shown  in 
Fig.  81.  In  this  case  an  oil  reservoir  is  formed  in  the  housing  of 
the  head-stock  A,  and  a  suitable  opening  in  the  form  of  a  slot  parallel 
to  the  axis  of  the  spindle  is  cut  through  the  lower  box.  Into  this  is 
fitted  a  flat  wick  B,  or  piece  of  coarse  soft  felt  whose  upper  edge 


FIG.  80.  —  Siphon  Oil  Cup. 


118 


MODERN   LATHE   PRACTICE 


rests  against  the  bottom  of  the  journal  C,  and  whose  lower  end  is 
immersed  in  the  oil  filling  the  reservoir.  Capillary  attraction  is 
depended  upon  for  drawing  the  oil  up  to  the  bearing,  although  with 
oil  at  the  height  shown  in  the  cross  section,  on  the  right  of  Fig.  81, 
the  oil  is  gradually  forced  up  to  the  under  side  of  the  journal. 


FIG.  81.  —  Lubrication  by  Capillary  Attraction. 

This  plan  has  the  advantages  of  keeping  the  journal  and  its 
lubricant  free  from  dirt;  of  straining  the  oil  so  that  any  dirt  it  may 
contain  will  not  reach  the  bearing;  of  providing  for  a  quantity  of 
oil  so  as  to  make  frequent  additions  to  the  supply  of  oil  unnecessary ; 
and  of  furnishing  a  handy  method  of  introducing  a  new  supply  of 
oil,  by  way  of  the  hole  D,  closed  by  the  stopper  E. 

In  large  machines,  using  a  con- 
siderable quo-:  tity  of  oil,  a  drain- 
age tube  is"  provided  through 
which  the  sediment  and  dirt  may 
be  gotten  rid  of  when  necessary. 
This  tube  is  closed  by  a  stopcock. 
This  method  of  lubrication  is 
very  largely  and  successfully  used 
in  countershaft  boxes,  which,  from 
their  comparatively  inaccessible 
position  are  very  liable  to  be  neg- 


FIG.  82.  —  Loose  Ring  Oiler. 


lected  in  the  matter  of  proper  lubrication. 

The  use  of  a  loose  ring  for  raising  oil  to  the  journal  bearing  is 
shown  in  Fig.  82.  In  this  case  a  loose,  flat  ring  B,  of  considerable 
larger  inside  diameter  than  the  diameter  of  the  journal  C,  is  placed 
around  it  and  allowed  to  hang  down  into  the  oil  in  a  reservoii 


LATHE  DESIGN:  THE  SPINDLE  BEARINGS,   ETC.        119 

formed  in  the  head-stock  A,  similar  to  that  shown  in  Fig.  81.  The 
revolution  of  the  spindle  is  usually  sufficient  to  keep  the  ring  in 
motion  so  as  to  draw  up  a  sufficient  supply  of  oil  to  lubricate  the 
bearing.  In  this  case,  also,  oil  may  be  introduced  through  the  hole 
D,  usually  closed  by  the  stopper  E.  One  ring  is  sufficient  for  a 
bearing  and  is  placed  in  the  center  of  it,  the  box  or  box  lining  ma- 
terial being  grooved  out  for  this  purpose. 

In  Fig.  83  is  shown  a  similar 
device  to  the  above,  except  that  a 
flat  linked  chain  is  used  instead  of 
a  circular  ring.     It  is  obvious  that 
by  lengthening  the  chain  it   will 
necessarily  dip  deeper  into  the  oil 
than  a  circular  ring  possibly  could, 
while  the  openings  in  the  links  of 
the  chain  will  more  readily  carry 
up  the  oil  than  will  a  smooth  ring 
devoid  of  openings  or  raised  parts.     Fl<5'  83'  ~  The  Loose  Chain  Oiler' 
In  both  the  above  cases  an  internal  groove  is  cut  in  the  inside  of 
the  journal  box  to  accommodate  the  ring  or  chain,  and  an  opening 
made  entirely  through  at  the  bottom  for  the  entrance  of  the  oil. 


FIG.  84.  —  The  Lodge  &  Shipley  Type  of  Oiler. 

A  modification  of  the  ring  device  is  shown  in  Fig.  84,  which  illus- 
trates a  type  of  lubrication  used  in  the  Lodge  &  Shipley  lathes.  It 
consists  of  a  ring  B  fixed  to  the  journal  and  having  formed  upon  it 
four  buckets  G,  G,  G,  G,  opening  in  the  direction  of  rotation,  whose 
function  is  to  dip  up  the  oil  as  they  pass  through  the  reservoir  and 


120  MODERN   LATHE   PRACTICE 

to  pour  it  over  the  journal  as  they  successively  pass  over  the 
highest  point  of  their  revolution.  Suitable  ducts  distribute  the 
oil  length  wise  of  the  bearing  and  return  it  to  the  oil  reservoir 
to  be  used  again  and  again.  Thus  a  positive  provision  is  made 
for  supplying  the  journal  with  oil,  and  the  manufacturers  assert 
that  a  spindle  so  fitted  up  will  run  for  a  month  without  a  new 
supply  of  oil.  The  oil  reservoirs  are  said  to  hold  about  a  pint 
and  the  supply  is  introduced  through  the  oil  hole  D,  which  is  pro- 
vided with  the  glass  tube  F,  closed  by  the  stopper  E,  and  through 
which  the  height  of  the  oil  in  the  reservoir  may  be  observed 
through  the  opening  cut  in  the  metal  surrounding  the  glass  tube 
as  shown  in  the  engraving. 

The  practical  utility  of  such  a  means  of  lubrication  is  at  once 
apparent,  as  the  neglect  of  workmen  to  attend  to  the  proper  lubri- 
cation of  lathe  spindles,  as  well  as  many  other  parts  of  the  machine 
where  oil  is  necessary,  is  one  of  the  most  fruitful  sources  of  lathe 
difficulties  that  occur.  And  a  spindle  that  has  been  allowed  to 
"run  dry"  and  its  finely  ground  and  polished  surface  to  become 
cut  and  "roughed  up"  is  very  difficult  to  ever  get  in  as  good  working 
condition  again  as  before  this  kind  of  abuse  happened. 

The  author  has  known  of  instances  where  the  designer  had  pro- 
vided an  oil  reservoir  which  had  been  filled  when  the  lathe  was  being 
tested  and  which  had  operated  well  and  lubricated  abundantly. 
The  lathe  was  shipped  to  a  customer,  set  up  and  run,  and  in  a  few 
months  the  parts  returned  completely  destroyed  from  lack  of  lubri- 
cation, the  fact  being  evident  that  no  oil  had  ever  been  placed  in 
the  reservoir  when  the  supply  first  introduced,  as  above  stated,  was 
exhausted.  Such  neglect  of  the  most  ordinary  precautions  is  a 
good  illustration  of  the  very  poor  shop  conditions  which  still 
exist  in  some  otherwise  well-managed  shops. 

The  gearing  in  the  head-stock  of  a  lathe  by  which  the  speed  of 
the  spindle  is  varied  is  in  general  terms  called  the  "back  gearing," 
since  the  purpose  of  it  is  to  "gear  back,"  that  is,  to  reduce  the  speed 
of  the  spindle. 

There  are  three  methods  of  changing  the  speed  of  the  spindle, 
namely:  by  running  the  driving-belt  on  the  different  steps  of  the 
cone;  by  means  of  the  usual  back  gearing;  and  by  means  of  what 
might  be  termed  a  secondary  back  gear,  or  as  generally  termed  the 


LATHE  DESIGN:  THE  SPINDLE  BEARINGS,   ETC.        121 


"triple  gear."     This  is  by  some  manufacturers  of  lathes  called  the 
1  double  back  gear." 

In  Fig.  85  is  shown  a  diagram  of  the  driving  mechanism  of  a 


Countershaft,  140  R.P.M. 


FIG.  85.  —  Diagram  of  the  Driving  Mechanism  of  a  Back  Geared  Lathe. 

back  geared  engine  lathe.  At  the  top  of  the  engraving  is  shown 
the  countershaft  cone  A,  as  this  performs  an  important  part  in  the 
changing  of  speeds.  The  spindle  cone  B  runs  loose  upon  the  lathe 
spindle  and  is  fixed  to  it  at  will  by  a  lock  bolt  passing  through  the 
face  gear  C,  which  is  permanently  keyed  to  the  spindle.  U#on  the 


122  MODERN   LATHE   PRACTICE 

small  end  of  the  cone  is  fixed  the  cone  pinion  D,  which  meshes  into 
the  back  gear  E,  which  is  fixed  at  one  end  of  the  back  gear  quill,  or 
sleeve  G,  which  carries  at  its  opposite  end  the  quill  pinion  F.  This 
quill  runs  freely  upon  a  shaft  called  the  back  gear  shaft,  which  is 
provided  at  each  end  with  eccentric  bearings,  and  at  one  end  a 
lever  for  operating  them,  by  means  of  which  the  back  gear  quill  G, 
with  the  back  gear  E  and  quill  pinion  F,  may  be  thrown  out  of 
engagement  with  the  cone  pinion  D  and  the  face  gear  C. 

The  operation  of  the  device  is  as  follows:  the  cone  B,  rotating 
the  cone  pinion  D  at  a  certain  speed,  and  the  back  gear  E  being 
engaged  with  it,  will  rotate  the  latter  at  a  speed  proportional  to  the 
number  of  teeth  in  the  two  gears.  In  this  case  the  cone  pinion 
D  having  32  teeth,  and  the  back  gear  E  having  88  teeth,  the  ratio 
of  their  respective  revolutions  will  be  as  2f  to  1 ;  therefore,  if  the 
cone  were  running  at  275  r.p.m. (revolutions  per  minute),  the  back- 
gear  quill  would  run  at  100.  This  speed  is  still  further  reduced  by 
the  quill'  pinion  F  and  the  face  gear  C.  These  two  have  respectively 
24  and  96  teeth  and  consequently  a  ratio  of  4  to  1,  so  that  the 
spindle  speed,  by  the  introduction  of  the  back  gears  and  the  with- 
drawal of  the  lock  bolt  attaching  the  cone  B  and  the  face  gear  C  to 
each  other,  will  be  reduced  to  25  revolutions. 

Therefore,  if  we  divide  the  revolutions  per  minute  of  the  spindle 
cone  by  the  ratio  of  the  cone  pinion  with  the  back  gear  multiplied 
by  the  ratio  of  the  quill  pinion  with  the  face  gear,  we  obtain  the 
spindle  speed.  Or,  in  detail,  in  this  case,  88-^32  =  2.75,  and 
96  -r-  24  =  4,  and  2.75  X  4  =  11,  which  is  the  combined .  ratio  or 
the  normal  back  gear  ratio.  In  short,  the  cone  speed  divided  by 
the  back  gear  ratio  will  give  the  spindle  speed,  thus :  275  -^11  =  25. 

The  various  speeds  given  to  the  spindle  cone  by  belt  changes 
depend,  of  course,  upon  the  porportions  of  the  diameters  of  the 
various  steps  of  the  cone.  When  there  are  five  steps  on  the  cone, 
the  central  step  on  each  cone  is  usually  of  the  same  diameter,  and 
as  the  two  cones  are  generally  cast  from  the  same  pattern,  so  far 
as  the  outer  shell  is  concerned,  it  is  simply  a  question  of  reversing 
one  so  that  the  belt  shall  be  on  the  largest  step  of  one  and  the 
smallest  end  of  the  other,  or  the  intermediate  step  above  or  below 
the  central  step. 

In  the  diagram  shown  the  steps  are  respectively  20,  17,  14,  11; 


LATHE  DESIGN:  THE  SPINDLE  BEARINGS,   ETC.        123 

and  8  inches  in  diameter,  and  the  ratios  as  follows,  viz. :  20  to  8  = 
2.5;  17  to  11  =  1.545.  These  ratios  multiplied  or  divided  (accord- 
ing as  to  whether  the  step  on  the  countershaft  cone  is  larger  or 
smaller  than  the  one  used  on  the  spindle  cone)  by  the  revolutions 


FIG.  86.  —  Diagram  of  the  Driving  Mechanism  of  a  Triple  Geared  Lathe. 

per  minute  of  the  countershaft  will  give  the  various  cone  speeds. 

Figure  86  is  a  diagram  of  the  driving  mechanism  of  a  triple 
geared  lathe.  So  far  as  the  countershaft  cone,  spindle  cone,  and 
the  back  gearing  are  concerned  it  is  identical  with  the  mechanism 


124  MODERN   LATHE   PRACTICE 

shown  in  Fig.  85,  except  that  the  quill  pinion  E  is  so  constructed 
as  to  slide  out  of  engagement  with  the  face  gear,  and  also  that 
there  is  a  third  gear  on  the  back  gear  quill  G,  namely  the  pinion 
H,  which  engages  the  gear  J  fixed  to  the  triple  gear  shaft  K, 
which  also  carries  the  internal  gear  pinion  L,  which  in  turn  engages 
the  internal  gear  M  fixed  to  the  back  of  the  face-plate  P,  which  is 
attached  to  the  front  end  or  nose  of  the  lathe  spindle  N. 

The  triple  gear  shaft  K  is  adapted  to  slide  endwise  in  its  bear- 
ings, and  to  be  retained  in  either  position  so  as  to  bring  the  gear  J 
and  pinion  L  out  of  engagement  with  the  pinion  H  and  internal 
gear  M  when  the  triple  gear  is  not  in  use.  This  position  is  repre- 
sented in  the  engraving  by  dotted  lines. 

As  the  pinion  H  has  30  teeth  and  the  triple  gear  J  has  90  teeth, 
the  ratio  existing  between  them  is  3.  And  as  the  pinion  L  has  20 
teeth  and  the  internal  gear  has  200,  their  ratio  is  10.  Therefore, 
these  two  ratios  multiplied  together  is  30,  which  multiplied  by  the 
ratio  of  2.75,  existing  between  the  cone  pinion  D  and  the  back 
gear  E,  produces  82.5,  which  is  the  triple  gear  ratio.  It  will  be 
noticed  that  in  this  calculation  the  face  gear  C  and  quill  pinion 
F  are  not  taken  into  account,  as  they  are  not  engaged  when  the 
triple  gear  is  in  operation. 

The  following  summary  of  back  gear  and  triple  gear,  as  well  as 
cone  conditions,  is  given  for  convenient  reference: 

Cone  diameters,  8,  11,  14,  17,  and  20  inches. 

Countershaft  speed,  140  revolutions  per  minute. 

Cone  pinion,  32  teeth;  back  gear,  88  teeth;  ratio,  2.75. 

Quill  pinion,  24  teeth;  face  gear,  96  teeth;  ratio,  4. 

Combined  ratio,  or  back  gear  ratio,  11. 

Triple  gear  pinion,  30  teeth;  triple  gear,  90  teeth;  ratio,  3. 

Internal  gear  pinion,  20  teeth;  internal  gear,  200  teeth;  ratio,  10. 

Combined  ratio  of  the  triple  gearing  alone,  30. 

Triple  gear  ratio,  including  first  back  gear  ratio,  and  as  is  usually 
given,  82.5. 

The  spindle  speeds,  with  the  countershaft  running  at  140  r.p.m., 
are  given  in  the  following  table: 


LATHE  DESIGN:  THE   SPINDLE   BEARINGS,   ETC.        125 


Cone  speeds  Back  Gears  and 
Triple  Gears  not  in  use. 

Back  Gear  speeds;  Triple 
Gears  not  in  use. 

Triple  Gear  speeds,  including 
first  Back  Gear. 

56.QO 
9t08 

5.09 

8.82 

.690 
1.175 

'  140.00 

12.72 

1.696 

216.30 

19.63 

2.621 

350.00 

31.81 

4.240 

To  graphically  illustrate  the  spindle  speeds  the  diagram  in  Fig. 
87  is  given.  The  principal  curve  beginning  at  the  bottom  of  the 
diagram  shows  the  five  cone  speeds  and  the  five  back  gear  speeds, 
while  the  diagram  at  the  top  on  a  much  larger  scale  gives  the  five 
triple  gear  speeds.  From  this  diagram  a  good  idea  of  the  propor- 
tions and  the  regular  progression  of  speeds  may  be  obtained. 
While  the  progression  of  speeds  shown  are  those  proper  under 
the  circumstances,  it  will  be  found  that  there  are  many  lathes  in  the 
market  in  which  they  are  not  realized,  often,  doubtless,  owing  to 
careless  designing.  In  making  this  statement  it  is  not  meant  that 
the  slowest  and  the  fastest  obtainable  speeds  are  not  proper..  It 
does  not  mean  that  the  high  speeds  are  not  fast  enough,  since  we 
can  readily  get  a  faster  speed  by  speeding  up  the  countershaft. 
In  the  same  way  we  may  obtain  a  slower  range  of  speeds  by  reduc- 
ing the  speed  of  the  countershaft. 

But  what  is  meant  is  that  as  between  the  three  series  of  speeds 
known  as  cone  speeds  (or  open  belt  speeds),  back  gear  speeds,  and 
triple  gear  speeds,  there  will  be  too  much  of  a  break  between  these 
divisions  or  groups,  or  there  will  be  an  overlapping  of  speeds  so  that 
one  or  two  speeds  of  one  group  are  very  nearly  duplicated  in  the 
next  higher  or  lower.  In  this  way  a  triple  geared  lathe  of  nominally 
fifteen  speeds  will  give  but  thirteen  practically  different  speeds. 
In  the  example  given  in  Fig.  87  it  will  be  noticed  that  the  speeds 
rise  in  a  very  regular  progression,  the  numbers  up  the  sides  of  the 
diagram  giving  the  speeds  and  those  beneath  giving  the  serial  num- 
ber of  the  fifteen  speeds  from  slowest  to  fastest. 

To  illustrate  some  of  the  common  faults  in  the  designing  of 
back  gears,  attention  is  directed  to  the  four  examples  shown  in 
Figs.  88,  89,  90,  and  91. 

In  Fig.  88,  there  is  too  much  of  an  increase  of  speed  between  the 


126 


MODERN  LATHE  PRACTICE 


7  8  9  10  11  12  1.8  U 

FIG.  87.  —  Speed  Curves  of  a  Triple  Geared  Lathe. 


50 


15 


fastest  speed  of  the  back  gear  and  the  slowest  of  the  cone  speed. 
This  amounts  to  a  difference  of  47  revolutions,  as  the  former  is 
48.9,  and  the  latter  96.  The  entire  range  of  speeds  is : 


LATHE  DESIGN:  THE  SPINDLE   BEARINGS,   ETC.        127 


Cone  Speeds 


395 

234 

149 

96 


Back  Gear  Speeds 


48.9 
29. 
18.4 
11.9 


The  countershaft  runs   130  revolutions  per  minute.    The    back 
gear  ratio  is  8.08  to  1. 

In  this  lathe  a  four-step  cone  is  used,  therefore  giving  only 
eight  speeds.  The  lathe  is  a  small  one,  the  swing  being  14  inches 
and  intended  for  light  work  and  a  comparatively  fast  range  of 


130  R.P.M. 


\S 


130  R.P.M. 


FIG.  88.  —  Back  Geared 
Lathe,  8  speeds. 


FIG.  89.  —  Back  Geared 
Lathe,  10  speeds. 


speeds.  It  will  be  noticed  that  the  countershaft  cone  is  consider- 
ably larger  than  the  spindle  cone,  which  is  an  unusual  condition. 

In  the  next  example  a  lathe  having  a  five-step  cone  is  selected. 
It  is  a  19-inch  swing  lathe  and  intended  for  much  heavier  work 
and  back  gears  having  a  much  wider  face,  in  fact  50  per  cent,  while 
the  pitch  of  the  teeth  is  in  about  the  same  proportion. 

Figure  89  shows  the  driving  mechanism  for  this  lathe,  whose 
back  gear  ratio  is  13.46  to  1,  and  whose  countershaft  speed  is  130 
revolutions  per  minute. 


128 


MODERN  LATHE  PRACTICE 


In  this  case  the  increase  of  speed  between  the  fastest  back 
gear  speed  and  the  slowest  cone  speed  is  23.7,  while  the  next  speed 
below  varies  only  10  revolutions,  which  is  a  palpable  fault  in  the 
caclulation  of  the  speed  progression.  The  following  are  the  spindle 
speeds : 

343.0 

206.0 


Cone  Speeds 


130.0 

82.2 
49.2 


Back  Gear  Speeds 


25.50 
15.30 
9.65 
6.10 
3.65 


For  this  size  of  lathe  the  highest  and  lowest  speeds  are  as  they 
should  be,  but  the  proper  progression  is  at  fault. 

Figure  90  is  a  diagram  from  a  lathe  of  17-inch  swing  and  having 
a  five-step  cone,  a  back-gear  ratio  of  12  to  1,  and  a  countershaft 
speed  of  150  revolutions  per  minute.  The  same  fault  of  too  great 
a  difference  between  the  fastest  back  gear  speed  and  the  slowest 
cone  speed  is  observed. 

The  spindle  speeds  are  as  follows: 


Cone  Speeds 


371.0 

231.0 

150.0 

97.5 

60.6 


Back  Gear  Speeds 


30.90 

19.25 

12.50 

8.10 

5.05 


The  difference  above  referred  to  is  29.7,  while  the  next  differ- 
ence below  is  only  11.35. 

The  next  example  is  of  a  30-inch  swing,  triple  geared  lathe  in 
which  the  speed  calculations  show  an  error  only  too  common  among 
lathes  of  this  type.  It  will  be  noticed  by  reference  to  the  engrav- 
ing, Fig  91,  that  the  countershaft  cone  is  considerably  larger  than 
the  spindle  cone,  which  is  entirely  unnecessary  since  the  same  object 
might  have  been  secured  by  running  the  countershaft  faster  and 
the  parts  need  not  be  so  heavy  or  expensive.  The  questions  of 
proportion  and  progression  of  speeds  can  be  easily  taken  care  of 
when  both  cones  are  alike,  if  the  proper  calculations  are  made. 

The  countershaft  speed  is  110  revolutions  per  minute. 


LATHE  DESIGN:  THE  SPINDLE   BEARINGS,   ETC.        129 


The  back  gear  ratio  is  15.23  and  the  triple  gear  ratio  57.74  to  1. 
The  spindle  speeds  are  given  below : 


Cone 
Speeds 


372.0 
212.0 
137.0 

88.7 
52.5 


Back  Gear 
Speeds 


24.40 

13.90 

9.00 

5.82 
3.45 


Triple  Gear 
Speeds 


6.44 
3.67 
2.37 
1.53 

.81 


By  reference  to  these  figures  it  will  be  seen  that  the  triple  gear 
speed  of  6.44  exceeds  both  the  back  gear  speeds  of  3.45  and  5.82, 
which  renders  them  comparatively  useless,  ^or  which  makes  the  two 


110  R.P.M. 


150  R.P.M. 


3 

:- 


FIG.  90.  —  Back  Geared 
Lathe,  10  speeds. 


FIG.  91.  —  Triple  Geared  Lathe, 
15  speeds. 


higher  speeds  given  by  the  triple  gears  of  no  effect  in  practical 
work.  Otherwise,  of  the  five  triple  gear  speeds  two  are  of  no  prac- 
tical use. 

Hence,  we  have  a  lathe  provided  with  fifteen  nominal  speeds, 
which  really  has  but  thirteen.  This  point  will  be  more  readily 
appreciated  by  referring  to  the  speed  curve  shown  in  the  diagram, 


130 


MODERN  LATHE  PRACTICE 


50 


16 


10 


1        2 


10       11       12       13       14       15 


FIG.  92.  —  Speed  Curve  of  a  Triple  Geared  Lathe 
Wrongly  Designed. 

Fig.  92,  and  the  faults  of  designing  more  clearly  brought  out  by 
comparing  this  diagram  with  the  two  curves  shown  in  the  diagram 
given  in  Fig.  87,  being  careful  to  note  that  the  upper  curve  repre- 


LATHE   DESIGN:    THE  SPINDLE  BEARINGS,   ETC.       131 

senting  the  triple  gear  speeds  is  drawn  to  a  scale  ten  times  larger 
than  the  curve  for  the  back  gear  speeds  and  the  cone  speeds.  The 
object  of  this  was  to  show  more  clearly  the  progressive  increase  of 
the  triple  gear  speeds,  whose  continued  upward  tendency  would 
properly  join  with  those  of  the  back  gear  if  the  latter  were  drawn  to 
the  same  scale,  which  the  dimensions  of  the  page  would  not  admit. 
The  figures  for  these  speeds  are  given  on  a  previous  page,  to 
which  the  reader  is  referred,  and  a  comparison  with  the  speeds 
given  in  the  last  example  is  suggested. 


FIG.  93.  —  Triple  Gearing  of  a  Lodge  &  Shipley  Lathe. 

In  the  diagrams  of  driving  mechanisms  in  Figs.  85, 86, 88, 89,  90, 
and  91,  the  countershaft  cone  is  shown  above  the  spindle  cone  and 
the  back  gear  and  triple  gear  mechanisms  below.  This  is  so 
arranged  for  convenience  in  giving  the  relative  dimensions  and 
proportions  of  the  parts.  While  it  is  the  usual  method  to  place 
the  back  gear  device  at  the  back  of  the  lathe  head-stock  or  in  the 
rear  of  the  spindle,  it  is  not  at  all  necessary  that  it  should  be  so 
placed,  and  in  fact,  on  some  of  the  larger  lathes,  it  is  placed  in  front 
of  the  main  spindle  as  a  matter  of  convenience. 

The  essential  parts  of  the  triple  gear  mechanism  in  connection 
with  the  usual  back  gears  are  well  represented  in  the  rear  view  of 
a  head-stock  shown  in  Fig.  93,  in  which  the  triple  gear  device  is 
shown  engaged  and  the  quill  pinion  thrown  out  of  engagement  with 


132  MODERN   LATHE   PRACTICE 

the  face  gear.  In  this  case  a  clutch  connection  between  the  back 
gear  shaft  and  the  triple  gear  shaft  serves  to  handle  the  pinions  on 
both  so  as  to  be  moved  into  and  out  of  engagement  at  one  and  the 
same  time,  thereby  running  the  lathe  as  a  back  geared  or  a  triple 
geared  lathe,  by  a  very  simple  and  convenient  change.  The  design 
is  of  a  lathe  built  by  Lodge  &  Shipley. 

While  it  is  not  the  intention  of  the  author  to  assume  to  present 
in  this  work  an  exhaustive  treatise  on  lathe  design,  for  the  reason 
that  the  scope  of  the  plan  is  not  extensive  enough  to  permit  it, 
and  for  the  further  reason  that  it  does  not  seem  necessary  in  view 
of  the  objects  for  which  it  is  written,  it  does  seem  thoroughly  in 
keeping  with  what  is  proposed,  to  give  such  facts  as  to  some  of 
the  more  important  points  of  design  as  will  serve  as  cautions  to 
the  designer,  as  interesting  lines  of  thought  to  the  machinist,  and 
as  information  to  the  buyer  of  lathes. 

These  have  been  the  considerations  governing  what  has  been 
presented  in  relation  to  back  gearing  and  triple  gearing  as  well  as 
dimensions  of  cone  steps. 

There  are  several  matters  intimately  connected  with  this  sub- 
ject which  seem  to  merit  still  further  consideration. 

Any  one  who  will  take  the  trouble  to  examine,  as  the  author 
frequently  has,  a  lot  of  lathes  in  almost  any  machine  shop  and  to 
make  the  most  superficial  calculations  of  their  speeds,  will  be  sur- 
prised at  the  amount  of  apparent  "guesswork"  that  has  entered 
into  their  design.  The  speed  curve  shown  in  Fig.  92  is  a  case  in 
point.  Narrow-faced  back  gears  without  any  calculations,  so  far 
as  one  may  see,  of  the  strain  which  they  must  bear;  small  pinions, 
whose  teeth  are  soon  ground  away  on  account  of  the  sharp  angles 
of  their  action;  a  lack  of  proper  proportion  between  cone  dimensions 
and  back  gear  dimensions;  and  many  other  similar  faults. 

We  have  all  seen  lathes  with  a  3-inch  vertical  belt  on  a  5-inch 
cone,  while  the  overhead  horizontal  belt  driving  the  countershaft 
was  4  inches  wide  on  a  15-inch  pulley;  when  every  mechanic 
knows  that  a  horizontal  belt  will  drive  more  than  a  vertical  one, 
aside  from  the  difference  in  the  diameters  of  the  pulleys  being  all 
in  favor  of  the  larger  pulley. 

When  we  consider  these  questions  we  cannot  avoid  the  conclu- 
sion that  there  have  been  many  good  opportunities  wasted  and 


LATHE  DESIGN:  THE  SPINDLE  BEARINGS,  ETC.        133 

that  the  money  spent  for  these  machines  should  have  produced 
much  more  really  practical  and  useful  machines  than  it  has,  and 
that  they  should  have  been  capable  of  turning  out  a  much  larger 
output  than  we  find  them  doing. 

In  designing  a  lathe  head-stock  the  triangle  formed  by  the  dis- 
tance from  center  to  center  of  the  inside  V's,  as  a  base,  and  the 
lathe  center  the  apex,  should  be  an  equilateral  triangle.  Sufficient 
material  must  be  provided  under  the  largest  step  of  the  cone  and 
the  face  gear  to  give  the  requisite  strength  and  rigidity.  The 
large  step  on  the  cone  should,  fill  the  remaining  space  with  the 
exception  of  a  sufficient  clearance  for  the  belt.  The  large  diameter 
of  the  cone  having  been  thus  fixed  the  diameters  of  the  other  steps 
are  a  question  of  proportion,  according  to  how  many  steps  there  are 
and  what  is  to  be  the  smallest  diameter.  It  is  common  practice 
to  make  the  steps  of  the  spindle  cone  and  the  countershaft  cone 
identical.  This,  on  a  five-step  cone,  will  give  a  spindle  speed 
(without  back  gears)  equal  to  the  countershaft  speed  when  the 
belt  is  on  the  middle  step.  The  spindle  speed  will  be  correspond- 
ingly faster  or  slower  according  as  the  belt  is  on  the  smaller  or  larger 
steps  of  the  spindle  cone,  and  in  the  same  proportion  as  the  cone 
steps  are  to  each  other. 

The  cone  diameters  having  been  fixed  the  back  gear  ratio  must 
be  made  to  correspond.  We  cannot  have  an  arbitrary  cone  pro- 
portion and  an  arbitrary  back  gear  ratio.  Only  one  can  be  fixed, 
and  the  other  must  be  arranged  to  correspond  with  it. 

A  homely  proportion,  but  one  that  will  come  out  very  nearly 
right  in  practice,  in  determining  the  proper  width  of  face  for  the 
cone  steps,  will  be  one  seventh  of  the  swing  of  the  lathe  when  no 
triple  gears  are  used.  If  triple  gears  are  used  it  is  common  practice 
to  make  the  belt  a  trifle  narrower.  The  present  tendency  is  towards 
wider  belts  and  it  seems  to  be  a  very  proper  development  made 
necessary  by  modern  shop,  conditions  and  the  use  of  high-speed 
steel  tools.  It  is  altogether  probable  that  belts  will  be  made  wider 
rather  than  narrower  in  the  future. 

There  is  also  a  tendency  to  make  the  differences  between  cone 
step  diameters  less,  which  gives  a  larger  diameter  to  the  smaller 
steps,  and  consequently  more  power  in  the  driving  mechanism  of 
the  lathe  and  avoids  the  necessity  for  very  tight  belts. 


134  MODERN   LATHE   PRACTICE 

Ordinarily,  the  width  of  the  face  gear  should  not  be  less  than 
eight  tenths  of  the  width  of  the  cone  steps,  and  the  width,  of  the 
back  gear  not  less  than  six  tenths.  Of  course,  the  pitch. -v 
teeth  should  be  in  proper  proportion  to  the  width  of  the  fact,  <1 
in  the  larger  lathes  the  pitch  of  the  teeth  of  the  face  gear  should  be 
one  number  coarser  than  that  of  the  back  gear. 

Usually  the  face  gear  has  an  outside  diameter  about  equal  to 
that  of  the  largest  step  of  the  cone,  but  should  not  be  larger.  The 
outside  diameter  of  the  cone  pinion  should  not  be  much  smaller 
than  the  smallest  cone  step.  These  dimensions  thus  coming  with- 
in rather  narrow  limits,  the  diameter  of  the  back  gears  and  that  of 
the  quill  pinion  will  be  governed  by  the  ascertained  or  the  arbi- 
trary back  gear  ratio. 

In  order  to  avoid  the  interference  of  a  large  back  gear  with 
the  desired  form  of  the  head-stock  at  this  point,  and  to  secure  a 
symmetrical  contour,  the  back  gear  shaft  can  advantageously  be 
raised  above  the  level  of  the  main  spindle.  This  is  permissible 
to  the  extent  of  1 J  inches  on  a  36-inch  swing  lathe. 

The  method  of  transmitting  the  power  from  the  spindle  to  the 
feeding  mechanism,  formerly  done  almost  exclusively  with  a  belt 
on  cone  pulleys,  one  of  which  was  upon  the  head  shaft  (located 
below  the  spindle  and  driven  by  it  through  the  medium  of  gears), 
and  the  other  on  the  feed  rod.  The  lead  screw  was,  of  course, 
driven  by  gears  so  as  to  obtain  a  positive  motion.  In  modern 
lathes  nearly  all  have  gear-driven  mechanism  for  both  the  rod  feed 
and  the  screw  feed. 

The  former  practice  of  reversing  the  feed  in  the  head-stock  is 
now  to  a  large  extent  abandoned,  and  this  function  performed  at 
the  apron,  and  is  much  more  convenient  to  the  operator. 

The  mechanism  for  driving  the  lead  screw  in  thread  cutting  and 
for  a  large  range  of  feeds  is  now  very  popular  and  is  accomplished 
wholly  by  gears  with  appropriate  levers,  shafts,  and  clutches.  Those 
for  driving  the  feed  rod  are  usually  known  as  "  variable-feed  de- 
vices" and  those  for  thread^ cutting  are  known  as  "rapid  change 
gear  devices."  It  is  not  unusual  to  find  these  combined  so  that 
one  set  of  variable-speed  gears  is  adaptable  to  both  functions. 

These  devices  will  be  considered  further  on  in  this  work,  and 
representative  inventions  for  these  purposes  will  be  given. 


CHAPTER  VII 
LATHE  DESIGN:  THE  TAIL-STOCK,  THE  CARRIAGE,  THE  APRON,  ETC. 

Functions  of  the  tail-stock.  Requisites  in  its  construction.  The  Pratt  & 
Whitney  tail-stock.  The  Reed  tail-stock.  The  Lodge  &  Shipley  tail- 
stock.  The  Blaisdell  tail-stock.  The  Hendey-Norton  tail-stock.  The 
New  Haven  tail-stock.  The  Prentice  tail-stock.  The  Schumacher  & 
Boye  tail-stock.  The  Davis  tail-stock.  The  American  Watch  Tool  tail- 
stock.  The  Niles  tail-stock  for  heavy  lathes.  New  Haven  tail-stock  for 
heavy  lathes.  The  Schumacher  &  Boye  tail-stock  for  heavy  lathes.  The 
Bridgford  tail-stock  for  heavy  lathes.  The  Le  Blond  tail-stock.  The 
lever  tail-stock.  The  lathe  carriage.  Requisites  for  a  good  design. 
Description  of  a  proper  form.  A  New  Haven  carriage  for  a  24-inch  lathe. 
The  Hendey-Norton  carriage.  The  Blaisdell  carriage.  The  New  Haven 
carriage  for  a  60-inch  lathe.  Criticisms  of  a  practical  machinist  on 
carriage  and  compound  rest  construction.  Turning  tapers.  The  taper 
attachment.  Failures  of  taper  attachments.  The  Reed  taper  attach- 
ment. The  Le  Blond  taper  attachment.  The  Lodge  &  Shipley  taper 
attachment.  The  Hamilton  taper  attachment.  The  Hendey-Norton 
taper  attachment.  The  New  Haven  taper  attachment.  The  Bradford 
taper  attachment. 

THE  function  of  the  tail-stock  is  to  support  the  end  of  the  piece 
of  work  opposite  to  the  head-stock;  to  furnish  a  movable  center 
for  various  forms  of  drills,  reamers,  and  similar  tools;  and  to  carry 
one  end  of  boring  bars  when  the  work  is  clamped  to  the  carriage. 

For  these  purposes  it  must  be  of  sufficient  strength  and  rigidity 
to  withstand  the  strain  to  be  put  upon  it;  it  must  have  a  traveling 
spindle  to  carry  the  tail  center;  and  be  capable  of  being  "set  over" 
in  a  direction  at  right  angles  to  the  center  line  of  the  lathe,  for  the 
purpose  of  turning  tapers,  and  in  some  types  of  lathes  for  boring 
operations. 

It  is  fitted  to  the  two  inner  V's  of  the  lathe  the  same  as  the 
head-stock,  so  as  to  permit  the  carriage  wings  to  run  past  it,  and 
must  be  capable  of  being  securely  clamped  in  any  position  along 

135 


136  MODERN  LATHE   PRACTICE 

the  length  of  the  bed.  The  spindle  must,  be  adapted  to  be  handled 
by  a  hand  wheel  upon  the  traverse  screw  in  small  and  medium 
sized  lathes,  and  in  large  lathes  located  conveniently  in  front1  and 
connected  with  the  screw  by  suitable  shafts  and  gearing.  The 
spindle  should  be  adapted  to  be  clamped  at  its  front  end  in  an 
efficient  manner  so  as  to  hold  it  firmly  and  at  the  same  time  not  to 
force  it  out  of  correct  alignment  with  the  head-stock  spindle. 

The  tail-stock  should  have  a  long  bearing  upon  the  V's,  which 
should  be  at  least  two  thirds  of  the  swing  of  the  lathe.  The  bolts 
for  clamping  it  down  should  be  considerably  nearer  the  front  than 
the  rear  end  so  as  to  counteract  the  lifting  tendency  due  to  pressure 
against  the  center.  In  lathes  of  12  to  30-inch  swing  two  bolts  will 
be  sufficient  to  rigidly  secure  it  to  the  bed.  In  larger  lathes,  four 
bolts  should  be  used. 

For  the  purpose  of  setting  over  for  turning  tapers  the  tail-stock 
is  composed  of  a  low  base  and  the  movable  part  of  the  tail-stock 
proper,  the  transverse  adjustments  being  made  with  a  cross  screw 
furnished  with  a  square  head.  The  two  parts  are  held  together  by 
the  holding-down  bolts  which  secure  the  tail-stock  to  the  bed. 
In  larger  lathes,  say  from  30-inch  swing  up,  the  division  between 
the  two  parts  is  near  the  top,  which  should  be  secured  by  an  ad- 
ditional set  of  four  bolts  so  that  the  spindle  may  be  set  over  with- 
out releasing  the  holding-down  bolts  which  secure  it  to  the  bed. 
Thus,  if  a  heavy  piece  of  work  is  supported  upon  centers  the  tail 
spindle  may  be  set  over  for  turning  tapers  without  removing  the 
work  from  the  centers. 

In  lathes  of  24-inch  swing  and  over  there  should  be  a  rack  and 
pinion  device  for  moving  the  tail-stock  to  any  desired  position  on 
the  bed.  In  lathes  of  36-inch  swing  and  over  this  device  should 
be  back-geared  so  as  to  give  sufficient  power  to  easily  move  the 
heavy  mass. 

This  back  gearing  should  begin  with  a  ratio  of  two  to  one,  and 
increase  as  the  lathe  is  larger  and  the  tail-stock  is  heavier,  so  that 
one  man  may  conveniently  do  the  work. 

Engravings  of  tail-stocks,  as  designed  by  prominent  builders, 
are  introduced  to  illustrate  these  conditions  and  the  manner  in 
which  they  have  been  met. 

The  Pratt  &  Whitney  tail-stock  is  shown  in  Fig.  94.    Its  par- 


LATHE   DESIGN:  THE  TAIL-STOCK,    ETC. 


137 


ticular  feature  is  the  overhang  at  the  front  end  for  giving  extra 
support  to  the  spindle.  The  spindle  is  larger  than  usual,  which 
gives  better  support  to  the  center  and  is  very  useful  when  using  it 
to  support  the  rear  end  of  a 
drill  or  reamer  when  long  holes 
are  to  be  drilled  or  reamed.  It 
is  secured  to  the  bed  by  an 


eccentric  and  lever  device 
which  is  quick  and  conven- 
ient.   

Figure    95    shows    a    front   FIG.  94.  —  14-inch  Lathe  Tail-Stock,  built 
view  of  a  Reed  tail-stock  for        b^ the  Pratt  &  Whi^ey  Company, 
a  27-inch  swing  lathe.     It  will  be  noticed  that  the  holding-down 

bolts  are  in  line  with  the  bed 
and  both  at  the  front  of  the 
upright  supporting  the  spindle 
sleeve.  They  are  so  placed  to 
permit  the  upright  to  be  cut 
away  in  front  so  as  to  permit 
the  compound  rest  to  swing 
around  to  a  position  much  nearer 
parallel  with  the  line  of  the  bed 
than  with  the  ordinary  form. 
A  rear  view  is  shown  in  Fig. 

FIG.  95. -Front  View  of  27-inch  Lathe    96>  which  is   of    the    same    tail- 
Tail-Stock,  built   by  the  F.  E.  Reed    stock  except  that  a  three-bolt 

crank  replaces  the  hand  wheel. 


The  form  of  the  casting  is  well  shown  as  seen  from  the  rear, 
form  is  called  the  "off-set  tail- 
stock." 

Figure  97  is  an  excellent 
view  of  the  Lodge  &  Shipley  type 
of  tail-stock  for  small  lathes,  and 
shows  their  device  for  clamping 
the  spindle,  and  the  mechanism 
of  the  tail-spindle  screw.  The 
contour  of  the  casting  might  be 
improved  so  as  to  appear  more 


This 


FIG.  96.  —  Rear  View  of  the  Reed 
Tail-Stock. 


138 


MODERN   LATHE   PRACTICE 


clean  and  symmetrical,  without  detracting  from  its  solid  and  sub- 
stantial appearance. 

Figure  98  is  the  tail-stock  used  on  20-inch  swing  lathes  built 
by  P.  Blaisdell  &  Company.  The  only  noticeable  feature  is  the 
unusual  diameter  of  the  tail-spindle  sleeve  in  proportion  to  its  sup- 


FIG.  97.  —  Tail-Stock  of  the  Lodge  &  Shipley 
Lathes. 

porting  parts.    The  cap  at  the  rear  end  is  of  such  form  and  dimen- 
sions as  to  increase  this  top-heavy  appearance. 

The  Hendey-Norton  tail-stock  for  20-inch  swing  lathes  is  shown 
in  Fig.  99.     It  is  a  clean,  symmetrical,  and  well-designed  piece  of 

work  and  a  considerable  improvement 
on  the  one  just  before  it.  It  is  se- 
cured to  the  bed  by  a  lever  and  eccen- 
tric arrangement  similar  to  that  shown 
in  Fig.  94. 

Figure  100  shows  the  New  Haven 
Manufacturing  Company's  tail-stock 
for  24-inch  swing  lathes.  A  finished 
sleeve  screwed  into  the  rear  of  the 


FIG.  98.  —  20-inch  Lathe  Tail- 
Stock,  built  by  P.  Blaisdell 
&  Company. 


main  casting  furnishes  the  support  for  the  tail-spindle  screw  and 
adds  to  the  otherwise  clean  outline  and  substantial  appearance  of 
the  base.  It  is  very  rigid  and  substantial. 

Figure  101  shows  the  Prentice  Bros.  Company's  tail-stock,  which 
they  claim  as  their  invention  so  far  as  American  lathes  are  con- 
cerned. Other  than  this  fact  there  is  nothing  particularly  notice- 


LATHE   DESIGN:  THE  TAIL-STOCK,   ETC. 


139 


able  in  its  design  except  that  there  are  two  ribs  and  grooves,  one 
to  each  bolt  for  preventing  the  undue  strain  on  the  holding-down 
bolts.  These  bolts  are  well  spread  apart,  which  is  a  good  feature  in 
some  respects  if  not  in  others. 


FIG.  99.  —  20-inch  Lathe  Tail-Stock, 
built  by  the  Hendey  Machine 
Company. 


FIG.  100.  —  24-inch  Lathe  Tail-Stock, 
built  by  the  New  Haven  Manufactu- 
ring Company. 


The  Schumacher  &  Boye  tail-stock  shown  in  Fig.  102  is  a  good 
general  design  and  resembles  that  of  the'  Hendey-Norton  manu- 
facture. Aside  from  the  very  prominent  cap  at  the  rear  end  it  is 
a  very  creditable  appearing  device,  and  considerably  better  than 
some  of  those  short  and  square  forms  which  appear  "  all  in  a  bunch," 
as  it  were. 


FIG.  101.  —  22-inch  Lathe  Tail-Stock, 
built  by  the  Prentice  Bros.  Company. 


FIG.  102.  —  18-inch  Lathe  Tail-Stock, 
built  by  Schumacher  &  Boye. 


Figure  103  shows  the  W.  P.  Davis  machine  Company's  produc- 
tion, which  is  of  fairly  good  proportions  and  has  ample  strength. 
While  it  is  for  only  a  28-inch  swing  lathe,  it  is  provided  with  a 
rack  and  pinion  device  for  moving  it  along  the  bed. 

The  Bench  lathe  tail-stock  is  well  shown  in  Fig.  104,  the  engrav- 
ing being  of  the  type  made  by  the  American  Watch  Tool  Company. 


140 


MODERN  LATHE  PRACTICE 


It  is  chiefly  noticeable  for  the  very  long  spindle  which  it  carries. 

This  type  of  tail-stock  does  not  usually  have  the  set-over  feature. 

It  is  clamped  to  the  bed  by  a  lever-nut  turning  horizontally. 

Of  the  heavier  tail-stocks, 
for  large  lathes,  the  Niles  type 
is  shown  in  Fig.  105.  This  is 
divided  near  the  bottom,  as  in 
the  usual  design  for  small  lathes, 
and  secured  to  the  bed  by  four 
bolts.  It  has  a  rack  and  pinion 
device  for  moving  it  along  the 
bed,  and  otherwise  is  of  ordinary 
design  and  construction,  with- 
out special  features  to  which  at- 


FIG.  103.  —  Tail-Stock  built  by  the  W. 
P.  Davis  Machine  Company. 


tention  need  be  called. 

The  tail-stock  shown  in  Fig.  106  is  of  the  same  general  form 
as  that  shown  in  Fig.  100, 
by  the  same   concern,   the 
New  Haven  Manufacturing 
Company.    This  is  for  a  60- 
inch  swing  lathe,  and  is  a 
very  massive  and  rigid  tail 
center  support.    It  has  pro- 
portionately a  lonff  bearing;       FIG.  104.  —  Bench  Lathe  Tail-Stock,  built 
,  .  ,     .,    .  by  American  Watch-Tool  Company. 

on  the  bed,  to  which  it  is 

secured  by  four  heavy  bolts.  It  is  divided  near  the  top  and  the 

upper  portion  secured  to  the  lower 

TI  _^nf\  fay  four  Other  bolts  of  ample  di- 

ameter, by  which  means  heavy 
work  held  on  the  centers  need  not 
be  removed  or  blocked  up  when 
setting  over  for  turning  tapers.  As 
the  spindle  sleeve  is  very  long  and 
the  tail  spindle  large  and  heavy, 
a  spur  gear  is  keyed  to  the  spin- 
dle screw  and  engages  a  spur  pin- 

FIG.  iqs.-42-inch  Lathe  Tail-Stock,     ion  on  a  shaft  in  front.     Upon  the 
built  by  the  Niles  Company.  front  end  of  this  shaft  is   a  miter 


LATHE  DESIGN;  THE  TAIL-STOCK,   ETC. 


141 


gear  which  engages  with  a  similar  one  fixed  to  a  short  transverse 
shaft  upon  whose  front  end  is  a  large  hand  wheel  by  which  the 
tail  spindle  is  easily  and  conveniently  operated.  The  ratio  of  this 
gearing  is  3  to  1.  The  tail- 
stock,  which  is  very  heavy  and 
massive,  is  moved  along  the 
bed  by  a  rack  and  pinion  de- 
vice, also  back-geared  at  a 
ratio  of  3  to  1,  by  which  one 
man  may  easily  move  the  tail- 
stock  from  one  point  to 
another,  although  it  weighs 
nearly  a  ton. 

The  establishment  of  Schu- 
macher &  Boye  make  a  some- 
what similar  tail-stock  for  their 
48-inch  swing  lathe.  It  is 
shown  in  Fig.  107.  It  is  pro- 
vided with  the  same  features 
as  the  one  just  considered,  but  has  the  hand  wheel  set  at  an  angle, 
with  the  intention,  probably,  of  rendering  its  position  more  con- 


FIG.  106.  —60-inch  Lathe  Tail-Stock, 
built  by  the  New  Haven  Manufac- 
turing Company. 


FIG.  107.  —  48-inch  Lathe,  built  by 
Schumacher  &  Boye. 


FIG.  108.  —  42-inch  Lathe  Tail- 
Stock,  built  by  Bridgford 
Machine  Tool  Works. 


venient  to  the  operator.    It  is  not  as  massive  or  rigid  as  the  last 
one  shown,  but  doubtless  serves  a  good  purpose. 

Figure  108  shows  a  design  of  tail-stock  made  by  the  Bridgford 


142 


MODERN   LATHE   PRACTICE 


Machine  Tool  Works  for  their  42-inch  swing  lathe.  It  is  of  peculiar 
design  and  the  base  has  the  appearance  of  having  been  "  built  up 
in  the  sand,"  from  the  pattern  designed  for  a  lathe  of  much  less 
swing.  It  is  not  a  handsome  design  by  any  means,  although  it 
probably  serves  the  purpose  of  supporting  the  tail  spindle.  It  has 
a  rack  and  pinion  device  for  moving  it  along  the  bed.  Its  length 
on  the  bed  is  not  as  great  as  it  should  be,  nor  do  the  holding-down 
bolts  seem  large  enough  for  a  lathe  of  42  inches  swing.  It  has  four 
bolts  for  holding  down  the  base  and  a  second  set  for  securing  the 
top  part  carrying  the  tail-spindle  sleeve. 

At  A,  Fig.  109  is  one  of  Le  Blond's  favorite  designs  and  which 

are  used  upon  most  of  the  lathes 
built  by  this  concern.  Its  pe- 
culiar feature  is  the  form  of 
the  tail-spindle  sleeve  with  its 
very  much  enlarged  front  end. 
While  it  has  a  strange  and  un- 
usual appearance,  its  form  is 
based  on  sound  principles  of 
construction  and  is  no  doubt 
practical  in  giving  more  sta- 
bility and  rigidity  to  the  tail 
center,  which  is  a  very  desirable  feature. 

From  the  foregoing  illustrations  and  descriptions  the  various 
features  of  tail-stocks,  made  by  the  different  manufacturers,  may 
be  quite  readily  studied  and  their  good  and  bad  points  duly  con- 
sidered, either  for  the  pur- 
poses of  designing  a  new 
lathe  or  for  purchasing  one 
suitable  for  the  special  line 
and  class  of  work  to  be  per- 
formed. 

At  B,  Fig.  110,  is  the 
ordinary  form  of  what  is 
known  as  the  "lever  tail- 
stock,"  which  is  mostly  used  upon  hand  lathes.  As  its  name  im- 
plies, the  tail  spindle  is  moved  lengthwise  by  a  lever  rather  than 
a  screw  and  hand  wheel. 


FIG.  109.  —  The  Le  Blond  Form 
of  Tail-Stock. 


FIG.  110.  — Lever  Tail-Stock  for  Hand 
Lathes,  built  by  the  F.  R.  Reed  Company. 


LATHE  DESIGN:  THE  TAIL-STOCK,   ETC.  143 

This  form  offers  facilities  not  possessed  by  the  other  form,  or 
possessed  in  a  less  convenient  form.  In  this  spindle  may  be  carried 
drills,  reamers,  etc.,  for  use  on  light  work  held  in  a  chuck.  It  may 
carry  a  small  face-plate  against  which  work  may  be  held  and  drilled 
or  reamed  by  a  drill  or  reamer  held  in  a  chuck.  It  may  carry  an 
inside  boring  tool,  and  if  made  with  a  " set-over"  device,  such  as  is 
used  on  the  tail-stock  of  an  engine  lathe,  its  usefulness  is  still  further 
extended,  particularly  when  working  brass  or  other  soft  metals  or 
materials.  This  design  is  by  the  F.  E.  Reed  Company. 

In  addition  to  all  the  requirements  thus  far  enumerated,  which 
a  lathe  must  possess  in  order  to  do  good  and  heavy  work,  it  must 
have  a  substantial  carriage  and  compound  rest  or  other  tool-hold- 
ing mechanism. 

The  carriage  must  support  the  compound  rest  on  top  and  the 
apron  hanging  down  at  the  front.  Through  the  latter  it  must  re- 
ceive its  driving  mechanism  as  the  lathe  is  now  constituted.  If  we 
were  to  design  a  lathe  with  a  view  only  to  the  theoretical  require- 
ments, we  should,  of  course,  put  the  device  for  moving  it  along  the 
bed  "on  the  cut/'  as  near  the  cutting- tool  as  possible,  and  there- 
fore the  lead  screw  and  feed-rod  would  be  inside  the  bed  and  at 
some  point  between  the  front  V  and  the  central  line.  But  we 
all  know  the  practical  objections  to  this  and  recognize  it  in  lathe 
design. 

There  are  a  few  points  in  the  design  of  a  good  lathe  carriage 
that  it  will  be  well  to  call  attention  to,  since  they  are  those  that  are 
frequently  lost  sight  of,  if  we  consider  many  of  the  present-day 
designs,  and  that  the  buyer  of  lathes  as  well  as  the  machinist 
will  do  well  to  give  attention  to. 

Figure  111  shows  the  design  of  an  ordinary  engine  lathe  car- 
riage intended  to  be  rigid  and  substantial.  It  has  a  wide  center 
part,  which  is  properly  supported  by  the  two  ribs,  thick  and  deep 
in  the  center.  The  only  opening  through  it  is  one  of  moderate 
dimensions  for  permitting  the  chips  to  pass  through. 

The  entire  top  is  on  one  level  so  that  large  work  to  be  bored 
may  be  bolted  down  upon  it  when  the  compound  rest  is  removed 
for  that  purpose.  Some  lathe  carriages  have  the  dovetail,  upon 
which  the  compound  rest  shoe  runs,  raised  above  the  general 
level  of  the  carriage.  When  work  is  to  be  bored  it  must  rest  upon 


144 


MODERN  LATHE   PRACTICE 


this  in  the  center  while  the  sides  are  supported  upon  parallels  with 
attendant  inconvenience  in  bolting  down  rigidly.  In  this  design 
there  are  four  T-slots  in  front  and  two  in  the  rear  for  the  accom- 
modation of  bolts,  while  others  may  be  passed  through  the  chip 
opening  in  the  center  if  necessary. 


FIG.  111.  —  Engine  Lathe  Carriage  Design. 

The  front  wings  of  the  carriage  are  broad,  for  the  purpose  of 
properly  accommodating  a  full  swing  rest,  an  additional  tool-post 
or  other  tool-holding  device.  The  T-slots  in  the  rear  may  serve  a 
like  purpose,  or  in  conjunction  with  those  in  front  serve  for  holding 
down  any  special  attachment  necessary. 

The  design  of  the  bed  is  such  as  to  furnish  additional  bearing 


LATHE   DESIGN:  THE  TAIL-STOCK,   ETC.  145 

surfaces  for  the  carriage  inside  of  the  V's,  the  inner  V's  being 
replaced  by  flat  surfaces,  thus  permitting  the  swing  to  be  increased 
and  the  carriage  very  materially  strengthened. 

The  carriage  is  gibbed  to  the  bed  on  the  outside  of  the  V's, 
both  back  and  front,  thus  spreading  the  gibbed  surfaces  as  far 
apart  as  possible. 

Following  this  will  come  in  due  order  illustrations  of  a  few  of  the 
carriages  and  compound  rests  built  by  some  of  the  prominent  manu- 
facturers. 

Figure  112  shows  the  carriage,  apron  front,  and  compound  rest  of 
a  New  Haven  24-inch  swing  lathe. 
The  T-slots  in  the  rear  wings  of  the 
carriage  are  as  shown  in  Fig.  Ill,  but 
those  in  the  front  wing  are  at  right 
angles.  In  some  cases  this  is  pre- 
ferable, but  if  the  carriage  is  to  be 
used  much  for  boring  purposes  the 
slots  will  be  found  most  desirable  if 
all  in  one  direction.  The  top  of  the 

carriage  is  level,  with   no   obstruc- 

.   .  FIG.  112.  —The  New  Haven 

tions  when  the  compound  rest  IS  re-  Carriage,  Apron,  and  Com- 

mMTaA  pound  Rest  for  Lathes  up 

to  32-inch  swing. 
The  apron  front  is  clear  of  gears 

and  other  similar  obstructions,  and  the  uses  of  the  levers  are  indi- 
cated by  plain  lettering  on  the  front  of  the  apron.  As  the  levers 
are  set  in  the  engravings  all  feeds  are  "out."  The  "star  nut" 
closes  the  friction  of  the  driving  bevel  gear,  and  the  feed  is  "on" 
to  the  right  or  left  according  as  the  lever,  marked  "to  reverse  all 
feeds"  is  thrown  to  the  right  or  left.  To  operate  either  the  lateral 
or  cross  feeds  the  upper  lever  is  thrown  to  the  left  for  "lateral 
feeds,"  and  to  the  right  for  "cross-feed."  The  lever  at  the  ex- 
treme right  closes  the  "split  nut"  on  the  lead  screw,  provided 
the  feeds  are  not  engaged.  That  is,  if  the  levers  are  as  shown 
the  lead  screw  nut  may  be  closed.  But  if  the  lever  "to  reverse 
all  feeds"  is  moved  to  the  right  or  left,  the  split  nut  is  locked 
"open"  and  cannot  be  closed. 

The  feed  rod  carries  two  bevel  pinions  arranged  in  a  sliding 
frame,  operated  by  the  lower  lever,  the  two  bevel  pinions  being 


146 


MODERN   LATHE   PRACTICE 


adapted  to  be  engaged  on  either  side  of  the  driving  bevel  gear  which 
transmits  the  motion  through  the  medium  of  a  conical  friction 
clutch  operated  by  the  "star  nut"  in  front  of  the  apron. 

Further  than  these  bevel  gear  connections  there  are  no  gears 
but  those  leading  up  to  the  cross-feed  screw  and  back  to  the  rack 
pinion  and  hand-wheel  shaft.  No  worm  or  worm-gear  is  used. 
Consequently  the  parts  are  large,  strong,  and  durable. 

The  compound  rest,  as  will  be  seen,  is  of  ample  proportions,  has 
a  graduated  base,  a  convenient  removable  double  crank,  and  a 
tool-post  provided  with  a  concave  ring  and  washer  adjustments 
for  the  tool. 

The  entire  mechanism  has  proven  very  satisfactory  in  practical 
use. 

The  Hendey-Norton  carriage,  apron,   and  compound  rest  is 

shown  in  Fig.  113.  It  is  not  as 
conveniently  arranged  in  front 
of  the  apron  as  in  the  last  ex- 
ample. The  carriage  has  the 
projecting  dovetail  in  the  cen- 
ter instead  of  the  flat  surface, 
and  only  two  T-slots  are  shown 
in  the  front  wing  of  the  car- 
riage. 

The  compound  rest  is  a  nice 
piece  of  designing  and  construc- 
tion. It  has  a  graduated  base 
and  a  tool-post  of  unusual 
strength  and  rigidity.  The 
single  crank  on  the  compound 
rest  screw  is  not  as  convenient  for  many  uses  as  a  double  crank. 
The  cross-feed  screw  carries  a  very  convenient  graduated  disc, 
which  ought  to  be  provided  for  all  lathes  up  to  32-inch  swing,  and 
is  useful  in  many  ways  for  even  larger  lathes  where  fine  work  is  to 
be  done. 

Figure  114  shows  the  carriage,  apron,  and  compound  rest  of 
the  Blaisdell  lathes.  While  the  construction  is  strong  and  sub- 
stantial, it  cannot  be  said  that  it  is  very  symmetrical  or  with 
any  attempt  at  fine  lines.  The  arrangement  of  the  apron  front  is 


FIG.  113.  —  The  Hendey-Norton 
Carriage,  Apron,  and  Compound 
Rest. 


LATHE  DESIGN:  THE  TAIL-STOCK,   ETC. 


147 


hardly  modern,  although  there  is  no  gearing  or  unnecessary  part 
exposed. 

A  single  T-slot  is  located  in  the  front  carriage  wing.  The  car- 
riage and  apron  are  the  same 
length,  which  usually  indicates 
that  the  bearing  of  the  carriage 
on  the  bed  is  not  as  long  as  it 
might  be  to  good  advantage. 
The  cross-slide  dovetail  projects 
above  the  general  level  of  the  car- 
riage so  that  it  would  be  in  the 
way  for  boring  operations. 

Figure  115  shows  the  front  of 


FIG.  114. — The  Blaisdell  Carriage, 
Apron,  and  Compound  Rest. 


the  carriage  and  the  compound 

rest  of   a   60-inch   swing,   New 

Haven  lathe.    The  top  of  the  carriage  is  level  and  has  three  T-slots 

on  each  side,  in  the  front  wings.     The  carriage  is  very  massive, 

weighing  about  1,600  pounds,  and  the  compound  rest  considerably 

over  half  that  amount. 

The  compound  rest  has  a  large,  circular,  graduated  base  and 
supports  a  very  broad  and  heavy  tool  block.    The  tool  is  held  by 


FIG.  115.  —  The  New  Haven  Carriage  and 
Compound  Rest  for  Large  Lathes. 

heavy  steel  clamping  bars  held  up  under  the  nuts  by  large  spiral 
springs  so  that  the  tool  may  be  readily  introduced.  These  clamp- 
ing bars  project,  at  the  ends,  beyond  the  holding-down  studs  so 
that  the  tool  may  be  placed  outside  the  studs  when  the  nature  of 
the  work  requires  that  position. 


148  MODERN   LATHE  PRACTICE 

The  entire  device  is  very  strong  and  rigid  and  capable  of  with- 
standing very  heavy  cuts.  There  is  a  power  cross  and  angular  feed 
in  addition  to  the  facilities  for  hand  feeding  in  all  directions. 

Further  illustrations  and  comments  upon  the  various  features 
of  this  class  on  the  lathes  built  by  different  makers  will  be  found  in 
later  chapters  of  this  work,  describing  the  entire  lathes,  and  to 
which  the  reader  is  referred  for  further  information. 

A  practical  machinist  has  recently  made  the  following  criti- 
cisms upon  one  of  the  popular  lathes  which  shows  the  standpoint 
from  which  the  practical  men  look  at  some  of  the  lathe  features. 
It  is  so  eminently  commendable  as  to  be  well  worth  preserving. 

First.  —  The  tool  block  will  not  travel  beyond  the  line  of  centers 
to  permit  holding  small  boring  tools  directly  in  the  tool-post  by 
means  of  any  of  the  holders  so  often  described  which 
use  V-block  clamps  and  make  a  handy  tool-holder.  This  distance 
is  short  8\  inch.  It  is  often  convenient  to  get  beyond  the  centers, 
and  to  my  mind,  at  least,  an  inch  is  a  great  advantage. 

Second.  —  The  stock  in  the  tool-post  is  so  short  that  it  is  impos- 
sible to  use  packing  on  top  of  the  tool  when  doing  delicate  work 
with  small  tools  made  of  wire  or  small  straight  bars,  and  without 
such  packing  the  value  of  this  style  of  tool  is  lost.  The  top  of  a 
J  x  1-inch  tool  can  be  raised  but  T36-  inch  above  the  centers. 

Third.  —  The  tool-post  screw  is  so  short  that  the  wrench  runs 
into  the  clamp  handle  of  the  tail  spindle,  and  either  the  rest  must 
be  removed  or  the  wrench  taken  off  and  the  screw  turned  with  the 
fingers  when  more  than  a  bare  loosening  is  required.  The  addition 
of  f  inch  to  the  length  would  avoid  this  difficulty  and  also  permit 
the  wrench  to  swing  clear  over  the  small  face-plate. 

Fourth.  —  The  key  in  the  lead  screw  for  change-gears  is  of  the 
Woodruff  style,  and  falls  out  every  time  a  gear  is  taken  off.  Of 
course  this  gear  does  not  require  changing  often ;  if  it  did  this  nuisance 
would  be  unbearable  and  call  for  a  properly  fitted  and  fastened 
key,  but  as  it  is,  the  gear  is  changed  so  seldom  that  one  forgets  this 
key,  and  so  it  drops  and  must  be  hunted  for  nearly  every  time  a 
gear  is  changed. 

Fifth.  —  The  centers  are  of  No.  2  Morse  taper,  but  the  holes  are 
reamed  just  enough  larger  or  deeper  so  that  no  tool  of  that  taper 
as  fitted  to  the  regular  Morse  socket  can  be  held  without  a  sleeve 


LATHE  DESIGN:  THE  TAIL-STOCK,   ETC.  149 

of  metal  or  paper.  This  may  have  its  advantages  in  preventing  the 
too  common  use  of  such  tools  in  the  center  holes,  but  is  sometimes 
a  great  aggravation  in  a  tool-room  lathe,  where  every  convenience 
would  be  duly  appreciated. 

Sixth.  —  The  face-plate  fit,  so  far  as  the  screw  thread  is  con- 
cerned, is  all  right,  but  the  part  chambered  out  next  the  shoulder 
is  TV  inch  larger  than  the  top  of  thread,  which  makes  it  quite 
difficult  to  start  the  thread  true  when  putting  on  plates  or  chuck, 
with  the  results  that  the  thread  often  jams  in  starting,  especially 
with  a  heavy  chuck. 

The  turning  of  tapers  is  often  accomplished  by  " setting  over" 
the  tail-stock  to  the  front  or  rear  as  may  be  desired,  so  as  to  be  out 
of  line  with  the  head-stock  center  and  thereby  inclining  the  axis 
of  the  piece  to  be  turned  with  the  axis  of  the  lathe.  While  this  is  a 
convenient  and  efficient  manner  when  the  taper  is  one  of  moderate 
inclination,  it  can  only  be  done  within  comparatively  narrow 
limits. 

We  must  therefore  resort  to  some  other  method  when  the  taper 
is  greater  than  will  be  possible  to  do  by  setting  over  the  tail-stock  and 
throwing  the  centers  so  much  out  of  line  with  each  other  as  to  wear 
them  out  of  shape  as  well  as  to  distort  the  form  of  the  center- 
reamed  holes  in  the  ends  of  the  piece  of  work. 

The  taper  attachment  was  devised  to  meet  this  condition  and 
consists  essentially  of  fixing  to  the  bed  a  bar  capable  of  being  ad- 
justed horizontally  to  any  desired  angle,  and  upon  which  is  fitted 
a  sliding  block,  moving  with  the  lathe  carriage,  and  so  attached  to 
the  tool-supporting  mechanism  as  to  cause  the  cutting-tool  to 
follow  in  a  line  parallel  to  the  inclined  bar  as  the  carriage  is  moved 
to  and  fro  on  the  bed.  This  is  accomplished  by  different  devices 
by  the  various  lathe  builders,  whose  efforts  are  usually  directed  to 
three  principal  objects:  first,  to  so  construct  the  taper  attach- 
ment that  it  may  be  attached  to  any  lathe  without  special  arrange- 
ment or  preparation  of  the  bed.  It  was  formerly  necessary  in 
nearly  every  case  to  have  planed  grooves  or  flat  surfaces  at  the  back 
of  the  bed  for  this  purpose  whenever  a  lathe  was  to  have  a  taper 
attachment  fitted  to,  or  sold  with  it;  second,  to  have  the  attach- 
ment so  designed  and  constructed  that  it  may  be  brought  into  use 
or  detached  with  the  least  possible  time  and  trouble;  and  third,  that 


150  MODERN  LATHE  PRACTICE 

the  parts  are  so  constructed  as  to  be  as  absolutely  rigid  as  possible, 
particularly  against  any  strain  that  would  tend  to  throw  them  out 
of  the  predetermined  line  of  inclination. 

Among  the  failures  of  taper  attachments  the  most  common  is 
that  of  turning  a  taper  so  that  the  inclined  line  of  the  surface  of  the 
turned  piece  is  curved  rather  than  straight;  sometimes  convex  and 
sometimes  concave.  The  operator  should  always  use  special  care 
to  have  the  attachment  perfectly  rigid  in  all  its  movable  parts, 
clamp  screws  tight  and  adjustments  perfect;  and  that  the  cutting 
tool  is  set  correctly  at  the  height  of  the  centers. 

Figure  116  shows  a  rear  view  of  the  taper  attachment  as 


FIG.  116.  —  Taper  Attachment  built  by  the 
F.  E.  Reed  Company. 

designed  and  constructed  by  the  F.  E.  Reed  Company.  The 
inclined  guide-bar  A  is  graduated  on  the  end  so  as  to  show  the 
amount  of  taper  that  is  being  turned.  This  bar  is  secured  to  a 
plate  B,  which  slides  upon  the  bar  which  is  attached  to  the  lathe 
carriage.  The  bar  A,  and  plate  B,  are  secured  against  longitudinal 
movement  by  means  of  the  rod  D,  secured  to  the  bracket  E, 
clamped  to  the  bed. 

By  this  means  there  need  be  no  special  preparation  of  the  bed 
of  a  lathe  in  order  to  use  the  taper  attachment.  The  carriage 
must,  however,  be  of  special  construction.  An  intermediate  slide 
E  is  proyided,  with  its  rear  end  pivotally  connected  with  the  slid- 
ing block  G,  which  travels  upon  the  inclined  bar  A  and  thereby 
produces  the  variation  of  alignment  in  the  travel  of  the  cutting- 
tool  necessary  to  turn  a  taper. 

The  inclined  guide-bar  A  may  be  minutely  adjusted  by  the 
screw  H,  which  may  be  placed  as  shown,  or  in  the  hole  shown  at  B, 
as  may  be  desired. 


LATHE  DESIGN:  THE  TAIL-STOCK,   ETC.  151 

It  would  appear  that  this  attachment  would  not  be  of  sufficient 
strength  and  rigidity  to  withstand  the  strain  of  heavy  turning  on  a 
very  severe  taper,  and  still  do  accurate  work. 

The  R.  K.  Le  Blond  taper  attachment  is  shown  in  Fig.  117. 
The  slide  supporting  bracket  A  is  attached  to  a  dovetail  formed 
upon  or  attached  to,  the  bed.  Upon  it  is  swiveled  the  guiding 
bar  B,  upon  which  is  fitted  the  sliding  block  C,  pivotally  connected 
with  the  compound  rest  shoe  D,  by  means  of  the  block  E  and  con- 
nection F. 


FIG.  117.  —  Taper  Attachment  built  by  the  R.  K. 
Le  Blond  Machine  Tool  Company. 

This  taper  attachment  is  of  new  design,  and  is  very  rigid.  It  is 
changed  from  straight  to  taper  work  by  simply  removing  a  taper 
pin  from  one  hole  to  another.  The  cross-feed  nut  is  never  discon- 
nected and  the  compound  rest  can  be  moved  by  the  screw  when 
turning  both  straight  and  taper  work. 

When  extra  heavy  work  is  done  the  compound  rest  can  be 
clamped  to  the  taper  attachment  by  a  brace.  By  this  arrangement 
all  thrust  is  relieved  from  the  screw,  insuring  greater  accuracy.  The 
guiding  bar  is  graduated  to  taper  per  foot  and  is  clamped  in  posi- 
tion by  two  T-slot  bolts.  A  graduated  screw  adjustment  is  provided 
for  accurately  setting  the  bar. 

Figure  118  shows  the  Lodge  &  Shipley  taper  attachment.  It  is 
constructed  in  a  similar  manner  to  that  made  by  the  F.  E.  Reed 
Company,  as  will  be  seen  by  the  engravings  of  the  two  devices. 


152  MODERN   LATHE   PRACTICE 

It  is  supported  by  the  carriage,  and  the  supporting  bar  upon  which 
the  inclined  guide-bar  A  rests  is  secured  against  longitudinal  move- 
ment by  a  rod  D  and  bracket  E;  the  latter  clamped  to  the  bed  the 
same  as  in  Reed's  device. 

The  taper  attachment  is  extremely  simple,  and  composed  of 
less  parts  than  any  in  the  market.    In  operation  it  is  changed 


FIG.  118.  —  Taper  Attachment  built  by  the 
Lodge  &  Shipley  Machine  Tool  Company. 

from  straight  to  taper  by  tightening  or  releasing  one  screw  on  the 
dog.  When  attached  for  taper  work  the  sliding  shoe  connects 
directly  with  the  tool-rest  and  not  with  the  screw,  making  its  opera- 
tion instantaneous.  The  nut  is  made  to  release  and  slide  in  a 
groove.  The  stud  for  the  sliding  shoe  also  engages  into  a  groove, 
and  to  attach  or  detach  requires  nothing  more  or  less  than  the 
releasing  of  one  screw  and  tightening  another,  or  vice  versa. 

The  cross-feed  nut  cannot  fall  over  as  in  ordinary  taper  attach- 
ment when  in  use,  because  it  is  never  disconnected.  The  bolt 
simply  slides  in  a  slot  in  the  compound  rest  slide. 

Figure  119  shows  the  taper  attachment  made  by  the  Hamilton 
Machine  Tool  Company.  Like  that  made  by  the  R.  K.  Le  Blond 
Machine  Tool  Company,  this  has  its  supporting  bracket  carried 
upon  a  slide  formed  upon  or  attached  to  the  bed.  It  is  thereby 
rendered  very  rigid  and  substantial.  The  swiveling  of  the  inclined 
guiding  bar  is  similar  to  those  already  described,  and  the  attach- 
ment of  the  connecting  block  to  the  cross-feed  screw  is  easily  under- 
stood by  reference  to  the  engraving  in  which  it  will  be  seen  that  the 
end  of  this  block  passes  through  the  bracket  attached  to  the  rear 


LATHE  DESIGN:  THE  TAIL-STOCK,   ETC. 


153 


cf  the  carriage.    The  sliding  block  runs  in  a  dovetail  in  the  inclined 
guide-bar  instead  of  on  a  square  raised  rib  on  top  of  it. 


FIG.  119.  —  T^per  Attachment  built  by  the  Hamilton 
Machine  Tool  Company. 

This  dovetail  form  is  not  at  all  necessary,  as  a  square  form  is  as 
good,  if  not  better,  and  much  more  economical.    There  is  no  ten- 


FIG.  120.  —  Taper  Attachment  built  by  the  Hendey 
Machine  Company. 

dency  to  lift  the  block  that  would  make  the  dovetail  form  advisable. 
The  Hendey-Norton  Taper  attachment  is  shown  in  Fig.  120. 


154 


MODERN  LATHE   PRACTICE 


It  is  supported  by  the  carriage  as  in  the  Reed  and  the  Lodge  & 
Shipley  designs,  and  travels  with  it  and  is  therefore  always  ready 
for  use.  All  operations  necessary  to  use  the  attachment  are  made 
from  the  front  of  the  carriage,  and  consist  of  first  setting  the  taper 
bar  to  any  desired  degree,  binding  the  sliding  bar  clamp  to  the  back 
V,  loosening  the  post  screw  at  the  end  of  the  carriage  arm  which 
releases  the  cross-feed  screw  connecting  block,  and  clamping  the  con- 
necting link  onto  the  taper-bar  slide  by  means  of  the  binding  handle. 
The  top  link  and  the  binding  bolt,  which  is  fitted  to  a  reamed 
hole  in  the  head  of  the  block,  furnish  a  double  connection  (and  one 
that  is  absolutely  rigid)  between  the  two  slides,  preventing  any 
back-lash. 


FIG.  121.  —  Taper  Attachment  built  by  the  New  Haven 

Manufacturing  Company. 

Figure  121  shows  the  taper  attachment  as  made  by  the  New 
Haven  Manufacturing  Company.  The  supporting  bracket  is  adapted 
to  travel  in  an  upper  and  lower  groove  planed  in  projecting  ribs  on 
the  back  of  the  bed,  thus  rendering  the  support  very  rigid.  The 
plate  B  is  heavy  and  rigid  and  supports  the  swiveling  guide-bar  C, 
upon  which  slides  the  block  D.  In  the  later  development  of  this 
device  the  dovetail  is  replaced  by  a  square  projecting  rib.  There 
is  also  an  improvement  in  the  connection  E  with  the  cross-feed 
screw,  consisting  of  a  heavy  flat  bar  attached  to  the  rear  of  the 
compound  rest  shoe  and  sliding  through  a  strong  and  rigid  guide 
block.  Its  rear  end  is  pivotally  connected  with  the  block  D,  mak- 
ing a  very  accurate  and  rigid  design. 

In  all  these  attachments  making  use  of  the  cross-feed  screw  as 


LATHE  DESIGN:  THE  TAIL-STOCK,   ETC. 


155 


an  adjusting  member,  it  must  be  so  arranged  as  to  be  detachable 
from  its  front  bearing,  or  permitted  to  slide  through  it  so  that  the 
inclined  movement  of  the  block  on  the  guide-bar  may  gradually 


FIG.  122.  —  Plan  of  the  Bradford 
Taper  Attachment. 

work  the  compound  rest  forward  and  back  to  form  the  taper  as 
the  cut  proceeds. 

Figure  122  is  a  plan  of  the  Bradford  taper  attachment,  and  Fig. 
123  is  a  cross  section  of  the  same  device.  It  is  of  the  type  of  carriage- 


FIG.  123.  —  Cross  Section  of  the  Bradford  Taper  Attachment. 


156  MODERN   LATHE   PRACTICE 

suspended  devices  similar  to  several  heretofore  shown  and  de- 
scribed. 

From  the  accompanying  sectional  view  it  will  be  seen  that  the 
rear  end  of  the  cross-feed  screw  is  held  by  collars  and  journaled 
in  a  bearing,  which  is  bolted  to  a  bar  connecting  it  with  the  sliding 
shoe  on  the  inclined  slide,  so  that  the  screw  always  moves  with  the 
bar  and  carries  the  compound  rest  with  it. 

The  tool  is  controlled  by  the  screw  at  all  times  without  inter- 
fering with  the  handle,  the  end  of  the  screw  telescoping  into  the 
sleeve  on  which  is  the  pinion  governing  the  power  feed.  Where 
it  telescopes  it  is  splined,  and  so  the  screw  is  under  control  of  the 
operator,  irrespective  of  the  position  of  the  tool  due  to  the  taper 
bar.  When  turning  tapers  the  lower  slide  of  the  compound  rest 
should  be  tightly  clamped  to  the  bar  by  the  square  head  screw, 
shown  in  cut.  Consequently  there  is  no  disconnecting  of  any  of 
the  parts  when  engaging  or  disengaging  the  attachment.  Simply 
tightening  the  dog  to  the  ways  brings  the  attachment  into  service, 
and  loosening  the  same  disengages  the  attachment,  leaving  the  lathe 
in  proper  shape  for  straight  work;  and  in  neither  case  does  the  use 
of  the  attachment  interfere  in  the  slightest  degree  with  the  full  and 
complete  use  of  the  compound  rest,  should  it  be  desired  to  face  off 
a  piece  the  full  swing  of  the  lathe. 

The  construction  further  makes  the  attachment  of  exceptional 
value  on  lathes  of  extra  length,  in  that  it  is  available  the  full  dis- 
tance between  centers  by  reason  of  its  being  bolted  to,  and  traveling 
with,  the  lathe  carriage. 


CHAPTER  VIII 

LATHE    DESIGN;    TURNING    RESTS,    SUPPORTING    RESTS,    SHAFT 

STRAIGHTENERS,    ETC. 

Holding  a  lathe  tool.  The  old  slide-rest.  The  Reed  compound  rest.  The 
Lodge  &  Shipley  compound  rest.  The  Hamilton  compound  rest.  The 
Hendey-Norton  open  side  tool-posts.  Quick-elevating  tool-rest. 
The  Homan  patent  tool-rest.  The  Le  Blond  elevating  tool-rest.  The 
Lipe  elevating  tool-rest.  Revolving  tool  holder.  The  full  swing  rest. 
The  Le  Blond  three-tool  rest.  The  New  Haven  three-tool  shafting 
rest.  The  Hendey  cone  pulley  turning  rest.  Steady  rests.  Follow  rests. 
The  usual  center  rest.  The  New  Haven  follow  rest.  The  Hendey 
follow  rest.  The  Reed  follow  rest.  The  Lodge  &  Shipley  follow  rest. 
Their  friction  roll  follow  rest.  Shaft  straighteners.  The  Springfield 
shaft  straightener.  New  Haven  shaft  straightener.  Lathe  counter- 
shafts. The  two-speed  countershaft.  Geared  countershafts.  The  Reed 
countershaft.  Friction  pulleys.  Tight  and  loose  pulleys.  Self-oiling 
boxes.  The  Reeves'  variable  speed  countershaft.  Design  of  geared 
countershafts.  Another  form  of  variable  speed  countershafts. 

WHILE  the  old  principle  of  holding  a  lathe  tool  in  a  tool-post  or 
under  one  or  more  clamping  bars  is  still  largely  used  to  securely 
hold  the  tool  in  a  rigid  position  for  performing  its  work,  there  have, 
within  the  past  few  years,  been  designed  and  come  into  use  a 
number  of  very  convenient,  rigid,  and  practical  tool-holding  devices! 

The  use  of  high-speed  steel,  and  consequently  of  heavy  cuts, 
have  rendered  the  use  of  very  rigid  tool-holding  devices  impera- 
tively necessary. 

Some  of  the  more  prominent  of  these  are  here  shown  and  their 
special  features  commented  upon. 

The  old  familiar  slide-rest  of  our  apprenticeship  days  still  lives 
and  is  much  used  on  hand  lathes,  bench  lathes,  and  the  like.  Fig. 
124  shows  this  form  of  turning  rest  as  made  by  the  F.  E.  Reed  Com- 
pany. Its  construction  is  so  familiar  to  every  mechanical  man 
that  any  description  is  unnecessary. 

157 


158 


MODERN   LATHE  PRACTICE 


Figure  125  shows  a  very  efficient  compound  rest  made  by  the 
same  establishment  to  which  attention  is  called  as  to  the  very  rigid 
method  of  holding  and  clamping  the  tool  by  two  heavy  clamping 


FIG.  124.  —  Plain  Slide-Rest,  made  by  the 
F.  E.  Reed  Company. 

screws.  Also  to  the  important  fact  that  the  tool  is  held  at 
the  extreme  left-hand  edge  of  the  tool-holding  device,  in  which 
position  it  is  nearly  always  used.  At  the  same  time  the  entire 
top,  tool-holding  block  is  adapted  to  turn  in  any  direction  and  to  be 
securely  held  at  any  angle,  thus  making  it  invaluable  for  turning  up 


FIG.  125. — Compound  Rest  made 
by  the  F.  E.  Reed  Company. 


FIG.  126.  —  Compound  Rest  for  Two 
Tools,  made  by  the  F.  E.  Reed 
Company. 


to  close  shoulders  or  other  obstructions  at  the  right,  and  also  when 
turning  or  boring  inside  work  wherein  it  is  necessary  to  set  the  tool 
nearly  parallel  to  the  center  line  of  the  lathe. 

Figure  126  shows  a  similar  device,  made  by  the  same  company, 
with  arrangements  for  holding  two  tools  under  the  same  conditions 


LATHE  DESIGN:  TURNING  RESTS,   ETC. 


159 


as  above  noted.  This  is  very  useful  when  heavy  cuts  are  to  be 
made  upon  work  where  rapid  reduction  of  the  amount  of  stock  is 
called  for,  as  the  inverted  back  tool  assists  very  much  to  balance  the 
resistance  by  dividing  it  between  two  points. 

Figure  127  is  of  the  compound  rest  and  tool-holding  device  as 
made  by  Lodge  &  Shipley.  It  is  neat  and  substantial  and  the 
forward  prolongation  of  the  shoe  adds  rigidity  on  heavy  cuts. 
Both  the  upper  and  lower 
slides  are  fitted  with  taper 
gibs,  which,  besides  being 
tapering,  are  tongued  and 
grooved  into  the  slides,  so 
that  no  amount  of  strain  will 
displace  them.  These  gibs 
are  provided  with  two  screws 
only,  and  at  each  end,  which 
take  up  the  wear  evenly  the 
entire  length,  and  are  possi- 
ble of  delicate  adjustment. 


FIG.  127. — Compound  Rest  and  Tool-hold- 
ing Clamps  made  by  the  Lodge  & 
Shipley  Machine  Tool  Company. 


They  will  not  require  resetting  perhaps  more  than  once  a  year. 

The-tool  clamping  bars  are  arranged  the  same  as  those  of 
the  New  Haven  device,  shown  in  Fig.  114.  These  slide  loosely 
into  the  T-slots  and  may  be  removed  and  replaced  by  the  arch  clamps 
shown  at  A,  A,  the  tool  passing  through  one  or  both  of  these  as 
occasion  may  require.  They  may  be  located  at  any  desired  position 
in  the  T-slots.  This  alternate  device  will  be  found  very  convenient 
on  many  unusual  jobs  as  well  as  upon  regular  work. 

In  Fig.  128  we  have  the  compound  rest  with  its  tool-clamping 
device  as  made  by  the  Hamilton  Machine  Tool  Company.  It  is 
quite  similar  to  that  shown  in  Fig.  124,  and  made  by  the  F.  E.  Reed 
Company,  and  possesses  its  good  advantages  of  adjustment  of  the 
tool  to  point  in  any  direction  and  to  work  up  closely  to  a  shoulder 
on  either  side.  Lodge  &  Shipley  make  a  similar  device  with  the 
tool  clamp  almost  identical  with  this  one. 

Figure  129  shows  the  "  open-side  tool-post"  made  by  the  Hendey 
Machine  Company.  It  is  so  arranged  that  it  may  be  substituted 
for  the  slotted  tool  block  and  ordinary  tool-post  of  their  lathes.  It 
may  be  swiveled  to  any  desired  angle  and  accurately  adjusted 


160 


MODERN  LATHE  PRACTICE 


by  the  graduations  at  the  base.    It  is  a  good  example  of  a  rigid 
and  substantial  tool-holding  device. 

Figure  130  shows  the  " quick-elevating"  tool-rest  made  by  the 
same  company.  The  tool  is  raised  or  lowered  by  using  the  tool-post 
wrench  on  the  short  lever  indicated  in  front  in  the  engraving.  It 
carries  the  old-style  tool-post  and  is  not,  therefore,  as  rigid  as  that 
shown  in  Fig.  128. 


FIG.  128.  —  Compound  Rest  and  Tool-holding 
Device,  made  by  the  Hamilton  Machine  Tool 
Company. 

Figure  131  shows  the  Homan  patent  tool-rest,  which  is  also 
made  by  the  Hendey  Machine  Company,  which  has  a  screw  adjust- 
ment as  to  height  and  a  graduated  base  for  setting  to  any  required 
angle.  It  is,  perhaps,  the  most  rigid  device  of  the  kind  using  a 


FIG.  129.  — Open  Side  Tool-Post, 
made  by  the  Hendey  Machine 
Company. 


FIG.  130.  —  Quick-Elevating  Tool- 
Post  made  by  the  Hendey  Ma- 
chine Company. 


single  tool-post,  and  is  a  very  well  made,  accurate,  and  convenient 
piece  of  mechanism. 

In  Fig.  132  is  represented  the  Le  Blond  elevating  tool-rest  pro- 
vided with  a  thread-chasing  stop  which  is  clamped  to  the  dovetail 
upon  which  the  rest  slides.  The  device  is  very  simple  and  effective 


LATHE  DESIGN:  TURNING  RESTS,   ETC. 


161 


for  ordinary  work.  It  would  not  seem  quite  so  well  adapted,  how- 
ever, for  very  heavy  cuts  on  account  of  the  fact  that  a  heavy  verti- 
cal strain  would  be  rather  severe  on  the  inclined  screw  which  holds 
the  tool  block  up  to  its  position. 


FIG.  131.  — The  Homan  Patent 
Tool-Rest  made  by  the  Hen- 
dey  Machine  Company. 


FIG.  132.  —  Elevating  Rest  with  Thread 
Chasing  Stop,  made  by  the  R.  K.  Le 
Blond  Machine  Tool  Company. 


A  very  substantial  device  is  shown  in  Fig.  133,  and  known  as 
the  Lipe  elevating  tool-rest.  It  is  made  by  the  Lodge  &  Shipley 
Machine  Tool  Company.  In  this  device  the  tool-holder  proper  has 
formed  upon  its  lower  end  a  cylindrical  portion  which  fits  into  the 
main  casting  and  is  secured  thereto  in  any  desired  position  by  a 
strong  clamping  screw.  It  is  ad- 
justed vertically  by  a  screw  through 
the  upper,  and  bearing  upon  the 
lower  casting  as  shown  in  the  en- 
graving. The  entire  device  fits 
upon  the  dovetail  of  the  carriage 
in  place  of  the  compound  rest. 
This  device  is  as  rigid  as  is  possible 
to  make  an  adjustable  tool-holding 
device  and  is  amply  strong  for 
heavy  cuts. 

The  revolving  tool-holder, 
shown  in  Fig.  134,  is  made  by  the  Lodge  &  Shipley  Machine  Tool 
Company,  the  R.  K.  Le  Blond  Machine  Tool  Company,  and  others. 
It  is  a  very  useful  form  and  is  equally  adaptable  to  the  carriage 
of  an  engine  lathe  or  the  slide  of  a  turret  lathe. 

It  is  a  very  strong  and  rigid  device  and  holds  four  tools,  either 
at  the  corners  or  sides.    The  locking  pin  withdraws  automatically 


FIG.  133.  —  The  "  Lipe  Elevating 
Tool-Rest,"  made  by  the  Lodge 
&  Shipley  Machine  Tool  Company. 


162 


MODERN  LATHE  PRACTICE 


when  the  clamping  bolt  is  released  to  revolve  the  turret.  It  is 
interchangeable  with  the  compound  rest,  simple  in  design,  rigid  in 
construction,  and  a  great  time-saver  where  the  number  of  pieces 

reduced  to  the-  same  dimensions  per- 
mits the  several  tools  in  the  tool-post 
to  be  used  alternately. 

Its  greatest  advantage  seems  to  be 
that  by  its  use  we  practically  add  the 
features  of  a  turret  to  the  ordinary 
engine  lathe  and  at  a  very  nominal 
cost.  It  is  true  that  we  do  not  get  the 
drilling  and  reaming  features,  but  still 
many  turret  operations  may  be  accom- 
plished by  its  use. 

Figure  135  shows  what  is  variously 
termed  as  a  "full  swing  rest,"  or  a 
"  pulley  rest,"  or  a  "wing  rest,"  etc., 
by  different  lathe  builders.  First,  be- 
cause it  is  for  turning  work  the  full 
swing  of  the  lathe  and  which  the  tool 
in  the  compound  rest  will  not  conven- 


FIG.  134.  —  Revolving  Tool- 
Holder,  made  by  the  Lodge 
&  Shipley  Machine  Tool  Com- 
pany. 


iently  reach ;  second,  because  it  is  principally  used  for  turning  pul- 
leys, and  work  of  that  nature,  and  third,  because  it  is  attached  to 
the  front  "wing"  of  the  lathe  carriage. 

It  is  frequently  made  at  an  angle, 
inclining  downward  from  the  center 
of  the  lathe  so  that  it  may  be  made 
conveniently  low  to  fit  the  low  car- 
riage of  a  large  swing  lathe  and  still 
have  the  general  line  of  the  tool  on  a 
radial  line  from  the  lathe  center. 
This  rest  is  practically  the  same  as 
the  plain  tool  block  used  on  the  car- 
riage, with  a  base  suitable  for  bolting 
down  over  a  T-slot. 

Figure  136  represents  a  three-tool  turning  rest,  adapted  to  be 
used  on  ordinary  engine  lathes.  It  is  made  by  the  R.  K.  Le  Blond 
Machine  Tool  Company. 


FIG.  135,  —  Full  Swing  Rest 
made  by  the  R.  K.  Le 
Blond  Machine  Tool  Com- 
pany. 


LATHE   DESIGN:  TURNING  RESTS,   ETC. 


163 


It  consists  of  a  special  base  or  slide,  carrying  three  tool-holders, 
two  in  front  and  one  in  back.  These  may  be  advanced  towards 
each  other  simultaneously  by  means  of  the  cross-feed  screw,  in 
addition  to  which  each  has 
an  independent  forward 
and  backward  movement. 
The  rear  tool-holder  has 
also  lateral  adjustment. 
The  base  is  surrounded  by 
a  groove  for  collecting  the 
oil,  soda-water,  or  other  lu- 
bricant used.  The  device 
is  invaluable  for  many 
purposes. 

Figure  137  shows  the  FlG  i36.  _  Three-Tool  Turning  Rest,  made 
three-tool  shafting  rest  by  the  R.  K.  Le  Blond  Machine  Tool  Corn- 
made  by  the  New  Haven 

Manufacturing  Company.  This  is  adapted  to  be  located  on  the 
carriage  of  an  ordinary  engine  lathe  in  place  of  the  compound 
rest,  and  in  addition  to  the  three-tool  slides,  tool-posts,  etc.,  in  the 


FIG.  137. —  Three-Tool  Shafting  Rest,  made  by 
the  New  Haven  Manufacturing  Company. 

last  example  there  is  a  fixed  standard  in  the  center  providing  a 
center  rest  in  which  bushings  of  various  diameters,  to  suit  the 
different  sizes  of  shafting,  may  be  carried,  and  which  serve  to 
hold  the  shafting  to  be  turned  steady  and  firm  for  the  action  of 
the  turning  tools.  In  the  last  example  this  function  must  be 


164  MODERN   LATHE   PRACTICE 

performed  by  a  separate  " steady  rest/'  attached  to  the  carriage 

or  to  the  lathe  bed. 

The  turning  of  cone  pulleys  is  usually  a  tedious  and  expensive 

job  unless  some  special  device  is  in  use  for  the  purpose.     In  Fig. 

138  is  shown  such  a  device  built  by  the  Hendey  Machine  Tool 

Company.  It  should  of  neces- 
sity have  a  special  carriage  to 
accommodate  it.  The  center 
part  of  the  carriage  should  be 
as  wide  as  the  length  of  the 
largest  cone  to  be  turned  in 
order  to  have  ample  support  for 
the  end  tools.  The  tool-carry- 
ing block  is  adapted  to  swivel 

FIG.  138.  —  Cone  Pulley  Turning  Rest, 

made  by  the  Hendey  Machine  Com-     SO  as  to  accommodate  the  loca- 

pany*  tions  of  the  tools  to  the  vary- 

ing diameters  of  the  cone,  as  the  difference  between  the  diameters 
of  the  smallest  and  largest  steps  will  necessarily  vary  considerable. 

As  one  T-slot  holds  all  the  tool-posts  it  is  only  necessary  to 
provide  as  many  tool-posts  as  there  are  cone  steps. 

The  crowning  of  the  pulley  faces  is  effected  by  a  taper  attach- 
ment device,  or  its  equivalent,  at  the  back  of  the  carriage.  This  may 
be  effected  by  using  straight  tapers  and  making  two  settings,  the 
inclined  lines  meeting  in  the  centers  of  the  pulley  faces;  or,  the  proper 
curve  or  " crown"  may  be  given  to  the  device  by  a  curved  guiding 
bar  instead  of  a  straight  one. 

Under  the  general  name  of  steady  rests  we  may  include  any 
attachment  to  a  lathe  which  has  for  its  purpose  or  function  that  of 
furnishing  a  support  at  one  or  more  points  around  the  circum- 
ference of  the  piece  being  turned,  opposing  the  pressure  of  the 
cutting  edge  or  point  of  the  tool  and  holding  the  work  up  to  its 
original  position  and  alignment  as  before  the  tool  commenced 
cutting. 

Ordinarily  there  are  two  classes  of  these  rests  which  may  in  a 
general  way  be  called  "center  rests "  and  " back  rests."  The  center 
rests  usually  have  jaws  bearing  upon  the  work  at  three  points 
spaced  equally  around  the  circle,  while  a  back  rest  bears  upon  the 
work  generally  at  the  back  and  on  top  only.  Sometimes  such  a  rest 


LATHE  DESIGN:  TURNING  RESTS,   ETC. 


165 


FIG.   139.  —  Center  Rest,   as 
made  by  nearly  all  Builders. 


consists  essentially  of  a  forked  or  V-shaped  piece  firmly  held  and 

embracing  the  circle  of  the  work. 

Sometimes  these  rests  are  attached  to  the  carriage  and  follow 

the  work  of  the  cutting-tool  closely  so  as  to  continue  the  support 

given  the  work  as  near  the  tool  as  possible.    These  are  often  called 

"  follow  rests."     They  may  be  made  with  two  or  three  adjustable 

jaws  resting  against  the  work,  or  they 

may  carry  a  bushing  having  a  hole 

reamed  just  large  enough  to  admit  of 

passing  rather  closely  over  the  work, 

sometimes  in  advance  of  the  work  (in 

case  of  previous  turning),  but  usually 

following  the  tool. 

Figure   139   is   of    the    well-known 

form  of  a  center  rest,  substantially  as 

made  by  all  lathe  builders,  the  varia- 
tions of  design  being  in  matters  of  de- 
tail, and  not  in  general  form,  functions 

or  methods  of  support  or  attachment. 

Figure  140  is  of  the  follow  rest  as  made  by  the  New  Haven 
Manufacturing  Company.  It  will  be  noticed  that 
the  top  jaw  inclines  to  the  front,  so  that,  acting  in 
conjunction  with  the  back  and  the  bottom  jaw, 
it  serves  to  embrace  more  than  half  of  the  circle 
of  the  work  in  the  process  of  turning.  The  base  of 
this  rest  is  fitted  to  the 
dovetail  on  the  lathe  car- 
riage and  fits  in  behind 
the  compound  rest. 

Figure  141  represents 

the  Hendey  follow  rest  for  use  on  light 

lathes.    It  is  bolted  to  the  side  of  the 

carriage  and   "steadies"   the  work   by 

means  of  the  adjustable  jaw  which  is  set 

up  against  the  back  and  top  of  the  piece 

to  be  turned,  and  held  in  that  position 

by  two  set-screws  as  shown. 

In  Fig.  142  we  have  the  follow  rest  used  by  the  F.  E.  Reed 


FIG.  140.  — The 
New  Haven 
Follow  Rest. 


FIG.  141.  — The  Hendey 
Follow  Rest. 


166 


MODERN   LATHE  PRACTICE 


FIG.  142.  —  The  Reed  Follow  Rest, 
with  Bushing. 


With  one 


Company.  This  rest  has  but  two  jaws,  one  at  the  rear  and  one 
over  the  work.  Its  peculiar  feature  is  that  the  jaws  may  be  re- 
moved and  a  special  piece  substituted,  which  is  bored  out  to  receive 

bushings  which  may  be  bored 
and  reamed  to  fit  the  different 
sizes  of  work  to  be  machined. 
This  feature  will  prove  advanta- 
geous, particularly  when  a  large 
number  of  parts,  say  shafts,  are 
to  be  turned. 

Figure  143  represents  a  very 
solid  and  substantial  follow  rest 
made  by  Lodge  &  Shipley  Ma- 
chine    Tool     Company.    It   is 
adapted  to  very  heavy  work  and 
will   be    found   useful    on    any 
rapid-reduction  lathe, 
exception  it  is  the  strongest  follow  rest  made. 

Figure  144  shows  the  strongest  fol- 
low rest  made  and  is  a  product  of  the 
same  establishment.  Being  provided 
with  friction  rolls  for  reducing  the 
friction  of  the  work,  it  is  adapted  to 
the  heaviest  work  the  lathe  is  capable 
of  carrying.  It  is  well  designed  for 
the  purposes  for  which  it  is  to  be  used 
and  its  parts  are  so  made  as  to  be 
easily  adjustable  to  suit  the  work. 
Its  special  points  of,  construction  are 
interesting  as  showing  the  thorough- 
ness of  the  design. 

The  two  jaws  carrying  hardened- 
steel  rollers  move  in  and  out  in  a  cir- 
cular path,  being  actuated  by  a  worm 
and  knob.  When  set  in  any  position 
they  are  adapted  for  a  variety  of 
diameters  by  simply  moving  the  en- 
tire rest  backward  or  forward.  This  is  accomplished  by  connecting 


FIG.  143.— The  Lodge  &  Shipley 
Follow   Kest. 


LATHE  DESIGN:  TURNING  RESTS,   ETC. 


167 


the  rest  to  a  screw  which  telescopes  the  regular  cross-feed  screw  and 
is  operated  by  the  same  hand  wheel  which  sets  the  tool-rest.  The 
position  of  the  rollers  is  such  that  in  approaching  a  shoulder 
they  support  the  shaft  upon  the  smaller  diameter  until  the  cutting- 
tool  has  turned  a  portion  of  the  next  larger  diameter,  when  the 
position  of  the  rest  is  changed  to  bear  on  that  portion. 

Those  having  quantities  of  shafts, 
with  a  number  of  shoulders  to  turn, 
will  recognize  in  this  rest  an  attach- 
ment entirely  new  in  principle  and 
of  the  greatest  importance  in  the  sav- 
ing of  time. 

One  of  the  indispensable  acces- 
sories or  attachments,  if  it  may  be  so 
called,  to  an  engine  lathe,  particularly 
one  provided  with  a  long  bed,  is  some 
kind  of  a  "straightener,"  by  which 
not  only  rough  bars  of  stock,  but 
partly  finished  and  finally  entirely 
finished  shafts,  may  be  straightened.  sPecial  RoUer  F 

The  general  plan  of  doing  this  work  is  to  rest  the  shaft  upon  two 
points  at  some  distance  apart  and  then  apply  pressure  on  the  oppo- 
site side,  and  at  a  point  midway  between  these  two  points. 

These  attachments  or  accessories  are  sometimes  attached  to 
the  carriage  of  the  lathe;  sometimes  mounted  so  as  to  slide  on  the 
V's  of  the  lathe;  again  upon  wheels  that  run  in  the  space  between 
the  inner  and  outer  V's;  and  in  still  other  cases,  for  small  and  com- 
paratively short  work,  they  are  mounted  upon  a  bench.  In  this 
case  they  either  have  attached  to  them  a  pair  of  centers  in  which 
the  work  to  be  straightened  may  be  placed  and  its  correctness  or 
incorrectness  as  well  as  the  location  and  extent  of  the  inaccuracies 
may  be  determined,  or  a  pair  of  V-blocks  in  which  the  shaft  may 
be  laid  while  being  straightened. 

In  Fig.  145  is  represented  one  of  the  latter  forms  of  this  acces- 
sory made  by  the  Springfield  Machine  Tool  Company,  the  uses  of 
which  will  be  readily  understood  by  any  mechanic.  It  is  intended 
to  be  placed  upon  a  bench  and  to  be  used  when  centering  work  by 
hand,  and  for  straightening  work  centered  by  hand  or  machine, 


FIG.  144.— The  Lodge  &  Shipley 
ollow  Rest. 


168  MODERN  LATHE  PRACTICE 

It  is  a  familiar  fact  that  work  straightened  in  a  press  is  more  likely 
to  remain  straight  in  the  lathe  than  when  hammered  straight,  and 
that  it  is  better  in  every  way. 

The  general  arrangement  of  this  machine  is  in  itself  very  con- 
venient, as  any  work  within  its  range  of  centers  may  be  tested  and 
straightened  without  the  unnecessary  walking  from  press  to  lathe 
each  time  in  straightening  rough  or  finished  work.  This,  how- 
ever, does  not  limit  the  length  of  shaft  that  can  be  straightened, 
as  any  length  may  be  operated  upon,  thus  making  it  a  great  labor 
saver. 


^xar 

FIG.  145.  —  Shaft  Straightener  for  Bench  Use,  made  by 
the  Springfield  Machine  Tool  Company. 

In  the  tool-room  it  is  especially  valuable,  not  only  for  centering 
and  straightening  work  in  the  rough,  but  for  straightening  pieces 
which  have  been  accidentally  sprung  in  use,  or  reamers,  etc.,  which 
have  been  sprung  in  tempering. 

The  blocks  upon  which  the  work  rests  when  being  straightened 
are  removable  to  or  from  the  screw  and  are  kept  in  line  by  tongues, 
which  fit  the  groove  shown.  The  shaft  is  movable  through  the 
arm  which  supports  it,  being  held  in  any  desired  position  by  the 
set-screw  shown,  which  has  a  piece  of  brass  over  its  points  to  avoid 
marring  the  shaft.  The  centering  heads  are  clamped  in  any  desir- 
able position  on  the  shaft,  by  the  binding  screw  shown.  The  top 
of  the  arm  which  supports  the  shaft  forms  a  pocket  for  chalk  or 
other  material  used  in  marking. 

The  center  at  the  right  is  pressed  forward  by  a  spring  and  has 
a  knurled  head  for  drawing  it  back,  both  centers  being  provided 
with  small  oil  wells.  The  body  of  the  machine  has  three  lugs 
cast  upon  it,  by  means  of  which  it  is  bolted  to  the  bench.  The  block 


LATHE  DESIGN:  TURNING  RESTS,   ETC. 


which  is  on  the  end  of  the  screw  is  of  cast  steel,  case  hardened,  and 
the  centers  of  tool  steel  tempered  —  the  whole  machine  being  so 
designed  and  constructed  as  to  make  it  worthy  of  a  place  and  useful 
in  any  tool-room  or  machine  shop  where  much  small  work  is  done. 
Figure  146  shows  the  shafting  straightener  made  by  the  New 
Haven  Manufacturing  Company.  The  base  A  has  cast  upon  it  at 
the  rear  a  curved  standard  B,  made  very  strong  by  proper  ribs  and 
extending  over  to  the  front.  Through  the  top  of  this  passes  a 
vertical  compression  screw  C,  running  in  a  long  bronze  nut  and 
carrying  loosely  upon  its  lower  end  a  V-block  D,  adapted  to  fit 


Fig.  146.  —  Shaft  Straightener  for  use  on  Lathe 
Bed,  made  by  the   New  Haven    Manufactur- 
ing Company.  s 

down  upon  the  round  shaft,  which  is  laid  into  two  other  loose  V- 
blocks  E,  E.  To  insure  great  rigidity  when  handling  large  work 
the  forged  stay  rod  F  is  provided,  its  head  being  held  in  a  T-slot 
in  the  base  casting  and  its  upper  end  in  a  slot  cast  in  the  head  and  in 
front  of  the  compression  screw  C,  and  secured  by  a  heavy  nut. 

At  each  corner  of  the  base  casting  is  bolted  a  leg  G,  G,  G,  G, 
carrying  loosely  journaled  therein  the  shafts  H,  H,  on  the  outer 
ends  of  which  are  fixed  the  wheels  J,  J,  J,  J,  which  are  adapted  to 
run  in  the  spaces  between  the  inner  and  outer  V's  of  the  lathe  bed, 
which  permits  it  to  be  moved  to  any  point  where  its  use  may  be 
desired. 


170  MODERN  LATHE  PRACTICE 

In  ordinary  cases  a  countershaft  is  a  very  simple  mechanism. 
In  the  older  form  of  engine  lathes  all  that  was  necessary  was  a  cone 
pulley  identical  with  the  spindle  cone,  and  upon  the  other  end  of 
the  shaft  a  tight  and  a  loose  pulley  for  receiving  the  driving-belt 
from  the  pulley  on  the  main  line  shaft.  Then,  as  threads  required 
a  backward  motion  of  the  lathe  spindle,  a  second  pair  of  pulleys 
was  added  and  a  cross-belt  applied  for  that  purpose.  The  shifting 
of  these  belts  was  too  slow  for  practical  work  and  clutches  were 
used.  These  were  of  the  old  "horn  clutch"  type,  making  consider- 
able " clatter"  in  their  use  and  starting  the  work  with  too  much 
shock. 

Later  on  friction  clutches  or  friction  pulleys  were  devised,  and 
these  in  one  form  or  another  are  largely  in  use  at  the  present  time. 

Up  to  a  comparatively  recent  date  the  lathe  had  but  two  speeds, 
so  far  as  the  countershaft  controlled  it.  One  was  the  usual  for- 
ward speed,  the  other  a  considerably  faster  speed  backwards,  mostly 
used  in  thread  cutting.  Occasionally,  for  special  work,  this  "back- 
ing" speed  was  taken  advantage  of  by  changing  the  cross-belt  for 
an  "open  belt,"  and  thus  getting  another  range  of  speeds.  Doubt- 
less this  suggested  the  advantages  of  a  regular  two-speed  counter- 
shaft which  has  now  become  quite  common,  as  a  convenient  and 
economical  method  of  adding  another  series  of  speeds  to  the 
lathe. 

There  are  now  used  on  a  number  of  popular  lathes  geared 
countershafts  as  well  as  various  devices  for  producing  a  variable 
speed  by  a  gradual  increase  or  decrease  of  the  number  of  revolutions 
per  minute.  This  result  has  been  sought  by  a  number  of  different 
devices  with  more  or  less  success.  Some  of  them  have  had  good 
features  to  commend  them  while  others  were  more  in  the  line  of 
makeshifts  that  accomplished  the  results  sought  very  inefficiently 
and  partook  too  much  of  the  nature  of  "traps"  as  understood  by 
the  machinist,  and  hence  were  comparatively  short-lived  and  un- 
popular. 

Figure  147  shows  a  good  example  of  the  regular  type  of  lathe 
countershafts.  It  is  made  by  the  F.  E.  Reed  Company,  and  con- 
sists of  the  cone  pulley,  a  counterpart  of  the  spindle  cone  part,  and 
two  friction  pulleys  mounted  upon  the  shaft,  which  is  supported  in 
two  hangers  having  self -oiling  boxes.  The  friction  pulleys  consist  of 


LATHE  DESIGN:  TURNING  RESTS,   ETC. 


171 


the  pulley  proper  A,  which  is  turned  on  the  inside  of  the  rim  for  the 
reception  of  the  friction  band  B,  or  has  cast  with  it  a  rim  projecting 
from  the  pulley  arms  and  finished  inside  for  the  same  purpose,  as 
shown  in  the  engraving.  The  friction  band  B  is  divided  at  one 
point  as  shown,  the  two  loose  ends  having  projecting  lugs  at  b,  6, 
drilled  for  pivot  bolts  by  which  it  is  connected  with  the  levers  C,  C, 
whose  ends  are  adjustably  connected  by  the  screw  and  nuts  shown 
at  d. 


Friction  Pulley, 
complete. 


FrictionJRing, 
or  Clutch. 


Wedge. 


FIG.  147.  —  Friction  Countershaft  for  Engine  Lathes,  made  by  the 
F.  E.  Reed  Company 

Sliding  upon  the  shaft  between  the  pulleys  is  the  clutch  collar 
E,  whose  horns  e,  e,  are  adapted  to  enter  between  the  ends  of  the 
levers  C,  at  /.  These  horns  being  wedge-shaped  will,  when  thrust 
between  the  free  ends  of  the  levers  C,  C,  spread  them  apart,  and  as 
their  fulcrum  ends  are  connected,  and  by  means  of  the  pivot  bolts 
connected  to  the  free  ends  of  the  friction  band  B,  tend  to  extend 
the  opening  of  this  band,  enlarge  its  diameter,  bring  it  in  contact 
with  the  inner  surface  of  the  pulley  (or  of  the  rim  cast  upon  it  for 
that  purpose),  and  cause  sufficient  friction  to  transmit  the  required 
power. 

The  clutch  collar  or  sleeve  E  is  provided  with  a  square  groove 
at  its  center  to  accommodate  the  shipper  fork,  by  means  of  which 


172  MODERN   LATHE   PRACTICE 

it  is  moved  to  and  fro  on  the  shaft,  according  as  one  or  the  other 
clutch  is  to  be  thrown  into  an  active  position  and  the  lathe  to  be 
driven  by  the  belt  on  the  one  or  the  other  pulley.  One  of  the  pulleys 
carries  an  open  belt  and  the  other  a  cross  belt. 

There  are  various  forms  of  friction  pulleys  and  friction  clutches 
used  on  countershafts,  but  all  are  designed  with  analogous  parts  to 
the  above  and  perform  similar  functions.  Therefore  there  is  no 
need  for  a  detailed  description  and  illustration  of  them.  In  all  of 
them  the  pulleys  run  loose  on  the  shaft,  except  when  clamped  to 
it  by  means  of  the  friction  device,  the  disc  or  friction  band  B,  or  its 
equivalent,  being  fixed  to  the  shaft. 

In  the  center  of  the  shaft  between  the  pulleys  is  usually  a  sliding 
sleeve  that  operates  the  friction  mechanism,  as  here  shown,  and 
by  which  it  is  connected  to  the  shipper  lever  within  easy  reach  of 
the  operator. 

The  tight  and  loose  pulleys  are  still  used  on  very  heavy  lathes, 
and  in  this  case,  when  both  the  forward  and  backward  motion  is 
desired,  there  is  one  tight  pulley  a  little  greater  in  width  than  the 
belt,  and  on  each  side  of  it  a  loose  pulley  of  double  this  width.  The 


-  .Exterior  View  -^Longitudinal  Section  Cross  Section 


FIG.  148.  —  Self-Oiling  Boxes  for  Countershafts,  made  by  the 
F.  E.  Reed  Company. 

belts  are  so  located  that  each  is  on  one  of  the  loose  pulleys  when 
the  shipper  handle  is  in  its  middle  position.  When  it  is  moved  to 
the  right  of  this  position  the  left  belt  is  moved  on  to  the  tight  pul- 
ley and  the  right  belt  travels  to  the  right  on  its  loose  pulley.  By 
moving  the  shipper  handle  to  the  left  the  reverse  effect  is  produced, 
and  the  right-hand  belt  becomes  operative.  The  pulley  on  the 
line  shaft  is,  of  course,  as  wide  as  all  three  on  the  countershaft. 

In  Fig.  148  is  given  a  good  illustration  of  the  self-oiling  counter- 
shaft box,  which  is  used  on  the  countershaft  shown  in  Fig.  146. 

As  will  be  seen  by  the  engraving  (Fig.  147),  the  journal  box  A 


LATHE  DESIGN:  TURNING  RESTS,   ETC.  173 

has  formed  beneath  it  an  oil  reservior  B  for  holding  a  quantity  of 
oil  sufficient  to  last  several  weeks.  Near  each  end  is  a  groove 
containing  a  wick  or  strip  of  felt  C,  C,  surrounding  the  shaft  and 
reaching  down  into  the  oil  reservoir  B,  by  means  of  which  an  ample 
supply  of  oil  is  always  delivered  to  the  journal  bearing.  The  wick 
may  be  introduced  and  oil  supplied  by  opening  the  hinged  covers 
D,D. 

As  the  supply  of  oil  is  so  profuse  there  is  the  liability  of  waste 
by  its  running  out  at  the  ends  of  the  journals.    This  is  prevented 


FIG.  149.  —  Reeve's  Variable  Speed  Count  ershalft. 

by  providing  the  return  oil  grooves  E,  E,  "at  the  ends,  which  con- 
duct the  oil  back  to  the  oil  reservoir.  The  design  and  arrangement 
is  very  simple  and  at  the  same  time  very  effective.  It  is  used  with 
slight  modifications  for  many  similar  purposes  with  like  success. 

In  Fig.  149  is  shown  the  Reeves'  variable  speed  countershaft, 
which  has  proven  a'  valuable  device  when  the  speeds  required 
are  not  excessive.  It  is  well  adapted  to  nearly  all  machine-shop 
tools  and  by  its  use  a  great  range  of  speeds  may  be  obtained. 

It  consists  of  two  shafts  B  and  C,  journaled  in  the  frame  A,  in 
the  usual  manner.  Upon  the  shaft  B  is  splined  the  rather  flat  cones 
D,  D,  and  similarly  connected  to  the  shaft  C  are  the  cones  E,  E. 
These  cones  are  adapted  to  slide  freely  to  or  from  each  other  on 


174  MODERN   LATHE  PRACTICE 

their  respective  shafts,  and  their  movement  is  governed  by  the 
levers  F,  F,  which  are  fulcrumed  at  /,  /,  and  pivotally  attached  to 
the  hubs  of  the  cones  D,  D,  E,  E,  by  suitable  collars.  The  farther 
ends  of  these  levers  are  pivotally  connected  to  a  screw  G,  by  suitable 
nuts  running  on  right  and  left  threads,  whereby  the  nuts  may  be 
drawn  together  or  forced  apart  as  may  be  necessary,  carrying  with 
them  the  ends  of  the  levers  F,  F,  and  consequently  the  cone  discs 
D,  D,  E,  E,  but  by  an  opposite  movement;  that  is,  as  the  discs  D,  D, 
approach  each  other  the  discs  E,  E,  recede  from  each  other.  Upon 
the  end  of  the  screw  G  is  the  sprocket-wheel  H,  from  which  a  chain 
runs  to  another  sprocket-wheel  near  the  operator,  who  may  handle 
it  by  means  of  a  crank  upon  the  shaft  of  the  latter  wheel. 

Running  within  the  cone  discs  D,  D,  at  one  end,  and  E,  E,  at 
the  other,  is  a  series  of  wooden  lags  connected  by  a  chain  mechanism 
by  which  it  becomes  in  effect  a  belt,  the  ends  of  the  lags  bearing 
against  the  inner,  inclined  surfaces  of  the  cone  discs. 

The  length  of  the  wooden  lags  being  constant,  it  follows  that  as 
the  cone  discs  are  forced  closer  together  the  lags  will  ride  up  on  a 
larger  diameter,  and  simultaneously  the  cone  discs  on  the  opposite 
shaft  will,  by  the  mechanism  described,  be  drawn  farther  apart, 
permitting  the  lags  to  run  closer  to  the  shaft  and  on  a  correspondingly 
smaller  diameter. 

Now,  as  one  of  the  shafts  B,  C,  is  driven  by  a  belt  from  a  pulley 
upon  the  main  line  shaft,  while  the  other  carries  the  pulley  (in  this 
case  a  cone  pulley)  driving  the  machine,  the  speed  of  the  same  may 
be  varied  at  will,  as  one  pair  of  cone  discs  are  forced  nearer  together 
and  the  other  pair  farther  apart,  thus,  in  effect,  changing  their 
relative  diameters  and  consequently  their  speeds. 

Geared  countershafts  are  also  used  upon  lathes  for  producing 
variable  speeds.  They  depend,  of  course,  upon  the  usual  methods 
of  Bringing  into  active  operation  pairs  of  gears  of  varying  diameters 
by  means  of  clutches,  sliding  gears,  and  similar  devices.  The  noise 
of  the  gears  is  one  great  objection  to  their  use.  This  has  been 
partially  avoided,  or  smothered,  by  enclosing  them  with  a  casing, 
which  partially  obviates  another  objection,  that  of  throwing  oil 
and  dirt  upon  the  floor,  the  machines,  and  the  workmen. 

Another  form  of  variable-speed  countershaft  was  brought  into 
use  some  years  ago  which  consisted  of  two  comparatively  long 


LATHE  DESIGN:  TURNING  RESTS,  ETC.  175 

cones  placed  side  by  side  but  in  reverse  positions  so  that  their  ad- 
jacent sides  were  parallel.  They  were  mounted  upon  parallel  shafts, 
one  being  the  driven  and  the  other  the  driver.  Motion  was  trans- 
mitted from  one  to  the  other  by  means  of  a  short  endless  belt  running 
between  the  surfaces,  with  the  slack  end  hanging  below  them.  This 
belt  was  controlled  by  a  sliding  belt  guide  by  means  of  which  it 
could  be  moved  from  end  to  end  of  the  cones,  whose  varying  diam- 
eters at  the  point  of  contact  determined  the  speed  transmitted 
from  one  shaft  to  the  other. 

While  this  device  was  entirely  operative  and,  with  light  loads, 
reasonably  successful,  it  was  not  well  adapted  to  transmitting  any 
considerable  amount  of  power,  owing  to  the  very  small  area  of 
contact  surface  between  the  cones  and  the  belt,  the  pressure  upon 
which  had  to  be  excessive  in  order  to  transmit  the  power  required 
even  for  light  work. 

Unusually  large  cones  would  no  doubt  have  added  materially 
to  its  transmitting  power,  but  as  a  practical  mechanism  it  was  not 
the  success  that  its  admirers  hoped  it  would  be. 


CHAPTER  IX 

LATHE   ATTACHMENTS 

Special  forms  of  turned  work.  Attachment  for  machining  concave  and 
convex  surfaces.  Attachment  for  forming  semicircular  grooves  in 
rolling  mill  rolls.  Device  for  turning  balls  or  spherical  work.  Turning 
curved  rolls.  A  German  device  for  machining  concave  surfaces.  A 
similar  device  for  convex  surfaces.  Making  milling  cutters.  Backing 
off  or  relieving  attachment.  Operation  of  the  device.  Cross-feed  stop 
for  lathes.  Grinding  attachments.  The  "home-made"  attachment. 
Electrically  driven  grinding  attachment.  Center  grinding  attachment. 
Large  grinding  attachment.  The  Rivett-Dock  thread-cutting  attach- 
ment. 

WHILE  an  engine  lathe  will  readily  turn  straight  and  taper 
work,  and  will  "face"  work  at  right  angles  to  the  center  line  of 
the  lathe,  or  by  means  of  the  compound  rest  will  turn  or  face  at 
any  angle,  no  means  is  provided  for  turning  curved  contours,  as 
spheres,  curved  rolls  smallest  in  the  center,  or  largest  in  the  center, 
as  the  case  may  be,  or  to  "face  up"  convex  or  concave  surfaces. 
These  and  many  other  forms  must  be  made  by  the  aid  of  some  kind 
of  a  device  built  for  the  special  purpose  and  usually  known  under 
the  general  name  of  a  "lathe  attachment." 

There  are,  of  course,  a  great  variety  of  jobs  that  can  be  economi- 
cally performed  on  a  lathe  if  we  are  provided  with  the  proper  tools 
and  a  suitable  "attachment"  for  handling  them. 

It  is  not  proposed  to  give  here  a  complete  Jist  of  these  ever  vary- 
ing kinds  or  types  of  lathe  attachments  or  to  exhaust  the  list  of 
forms  of  work  that  may  be  machined  by  one  or  another  of  these 
devices,  yet  it  may  be  interesting  to  present  a  few  of  the  attach- 
ments that  are  most  likely  to  be  needed,  and  in  a  general  way  those 
that  the  machinist  may  easily  make  for  himself. 

It  often  happens  that  a  large  number  of  concave  or  convex  sur- 

176 


LATHE   ATTACHMENTS 


177 


faces  have  to  be  machined  to  accurate  spherical  forms,  the  pieces 
being  of  such  dimensions  or  material  that  the  usual  forming  tools 
are  impractical,  or  that  the  variety  of  dimensions  would  render 
them  too  expensive. 

In  these  cases  a  special  device  must  be  designed  which  will 
properly  fulfil  the  conditions  and  be  capable  of  adjustment  within 
a  reasonable  range  of  diameters  of  the  work  and  the  radii  of  the 
curves  to  be  machined. 


FIG.  150.  —  Plan  of  Lathe  Attachment  for 
Forming  Concave  and  Convex  Surfaces. 

This  may  be  accomplished  by  a  special  device  attached  to  almost 
any  ordinary  lathe  having  a  compound  rest  with  a  circular  base, 
such  as  are  now  nearly  always  designed  and  built.  The  author 
has  had  occasion  to  design  several  of  these  devices,  and  the  general 
form  and  arrangement  of  them  has  been  as  shown  in  the  accom- 
panying engravings,  in  which  Fig.  150  is  a  plan  of  the  lathe 
carriage  showing  the  circular  feeding  device;  Fig.  151  is  a  front 
elevation  showing  the  method  of  varying  the  feed  to  suit  the 
material  to  be  machined;  and  Fig.  152  shows  a  modification  of 
the  device  for  a  different  form  of  work. 

The  various  forms  of  work  required  to  be  done  by  a  device  of 


178 


MODERN   LATHE  PRACTICE 


this  kind  are  most  frequently  for  concaving  vertical  step  bearings 
of  various  diameters  from  three  inches  up,  and  of  radii  varying  in 
proportion,  for  forming  concave  and  convex  surfaces  for  ball  and 
socket  joints,  for  turning  large  spherical  surfaces,  and  for  forming 
semicircular  grooves  in  rolls  for  rolling  iron  and  steel  bars. 

The  construction  and  application  of  this  device,  as  arranged  on 
an  ordinary  lathe,  is  as  follows.  A  machine  steel  ring  A  is  forged, 
turned  up,  bored  to  a  force  fit  to  the  circular  portion  of  the  com- 
pound rest.  Its  outer  surface  is  properly  formed  for  a  worm-gear, 
its  teeth  cut  and  hobbed  and  it  is  forced  on,  and  pinned  if  thought 
necessary.  Engaging  the  teeth  of  this  is  the  worm  B,  fixed  to  a 
shaft  C,  journaled  in  the  brackets  D,  D,  which  are  fixed  to  the  car- 
riage as  shown.  Upon  the  front  end  of  the  shaft  C  is  the  gear  E, 


FIG.  151.  —  Front  Elevation  of  Attachment. 

which  may  be  removed  and  another  size  substituted  for  varying 
the  rate  of  feed.  Upon  the  front  end  of  the  cross-feed  screw  F  is 
fitted  a  removable  gear  G.  Connecting  the  gears  E  and  G  is  the 
intermediate  gear  H,  carried  upon  a  movable  stud  located  in  the 
stud-plate  J,  which  is  pivoted  upon  a  projecting  sleeve  formed  upon 
the  front  bracket  D  and  held  in  any  desired  position  by  the  clamp- 
ing screw  K.  By  this  arrangement  the  rate  of  feed  may  be  con- 
veniently changed  to  suit  different  diameters  of  work  and  materials 
of  varying  degrees  of  hardness,  the  same  as  the  usual  change-gears 
of  a  lathe.  By  releasing  the  stud-plate  J,  the  gears  G  and  H  may 
be  thrown  out  of  engagement  temporarily,  while  the  stud-plate  J 
and  the  brackets  D,  D  may  be  easily  removed  altogether,  if  it  is 
desired  to  use  the  lathe  for  ordinary  turning  for  any  length  of  time. 
As  the  feed  for  this  device  is  derived  from  the  cross-feed  screw 


LATHE  ATTACHMENTS  179 

F,  it  is  necessary  to  replace  the  usual  solid  nut  in  the  shoe  by  a  split 
nut  (not  shown)  with  the  usual  lever  or  eccentric  device  for  open- 
ing and  closing  it  as  may  be  desired.  A  clutch  device  on  the  front 
end  of  the  cross-feed  screw  F  may  be  adopted,  if  desired,  by  having 
the  cross-feed  pinion  N  formed  upon  a  sleeve  projecting  through 
to  the  front  of  the  carriage  and  the  gear  G  mounted  upon  it,  and 
connected  with,  or  disconnected  from,  the  cross-feed  screw  F  by 
sliding  a  double-faced  clutch. 

In  using  this  device  for  concave  work  held  in  a  chuck  or  strapped 
to  the  face-plate,  care  must  be  taken  to  have  the  compound  rest 
so  adjusted  on  the  carriage  that  when  set  parallel  with  the  center 
line  of  the  lathe  its  center  will  be  exactly  under  that  line,  and  that 
the  horizontal  distance  from  the  point  of  the  tool  to  the  center 
of  the  compound  rest  will  be  the  exact  radius  of  the  curve  to  be 
produced. 

If  convex  work  is  to  be  done  the  compound  rest  tool  block  must 
be  drawn  back  far  enough  past  the  center  to  give  the  required 
radius  of  the  convex  curve. 

Figure  152  shows  a  compound  rest  tool 
block  arranged  for  forming  the  semicircular 
grooves  in  rolling  mill  rolls.  In  this  case  the 
tool-post  M  may  be  made  in  two  or  more  sizes, 
as  some  of  the  grooves  are  small  enough  to  ne-  ^g^f ' Attachment01 
cessitate  quite  a  small  tool-post.  If  a  lathe 
is  to  be  used  exclusively  for  this  work  the  compound  rest  may  be 
removed  entirely  and  a  circular  base  provided,  having  worm-gear 
teeth  cut  in  its  edge.  This  will  be  held  down  in  the  same  manner 
as  the  compound  rest,  and  have  fixed  in  a  raised  central  portion 
tool-posts  proper  for  the  work  for  which  it  is  designed.  In  any 
event  it  will  be  found  necessary  to  construct  the  device  in  as  strong 
a  manner  as  possible,  in  order  to  prevent,  as  far  as  may  be  the 
chatter  or  vibration  of  the  tool. 

The  device  as  shown  will  be  found  to  be  economical  to  make 
and  apply,  as  well  as  very  convenient  and  efficient  in  its  opera- 
tion. 

All  machinists  who  have  ever  undertaken  to  turn  balls  or  par- 
tially spherical  surfaces  know  how  difficult  it  is  to  produce  a  satis- 
factory piece  of  work,  either  as  regards  finish,  time  required,  or 


180 


MODERN   LATHE   PRACTICE 


accuracy.  In  Fig.  153  is  shown  a  compound  rest  containing 
an  attachment  for  doing  this  work.  In  Fig.  154  is  a  bottom  view 
of  the  same  for  the  purpose  of  showing  the  operative  parts. 

In  its  operation  the  lower  slide  or  shoe  A  of  the  compound  rest 
is  fixed  to  the  carriage.    The  cross-feed  nut  B  is  fixed  to  the  rack 


FIG.  153.  —  Side  Elevation  of  Ball  Turning 
Attachment. 


C,  which  engages  with  the  idle  pinion,  D,  which  in  turn  engages  the 
gear  E,  which  is  fixed  to  the  central  stem  of  the  compound  rest 
tool  block  F. 

When  in  use  the  cross-feed  is  connected  and  started,  and  in- 
stead of  moving  the  entire  compound  rest  across  the  carnage  as 
it  ordinarily  would,  it  moves  only  the  rack  C  forward  or  back, 
which  motion,  being  transmitted  by  the  pinion  D,  and  gear  E, 


FIG.  154.  —  Bottom  View  of  Ball  Turning 
Attachment. 

swings  the  compound-rest  tool  block  F  around  on  the  center  of  the 
gear  E,  the  shoe  A  being  fast  to  the  carriage. 

The  diameter  of  the  work  is  regulated  by  the  ordinary  compound 
rest  screw  crank  G,  in  the  usual  manner. 

The  turning  of  curved  rolls  such  as  shown  in  Fig.  155  is  not  pro- 


LATHE  ATTACHMENTS 


181 


vided  for  in  the  ordinary  attachments  sold  with  an  engine  lathe, 
and  where  this  work  is  not  done  regularly  so  as  to  warrant  the 
designing  and  building  of  an  at- 
tachment for  the  purpose,  some 
mechanism  must  be  arranged  for 
doing  the  work. 

The  engravings  in  Fig.  156, 
which  is  a  cross  section,  and  Fig. 
157,  which  is  a  plan,  show  how  an 
ingenious  machinist  managed  to 
do  this. 

In  the  engravings,  A  is  the  bed 
of  the  lathe,  B  is  the  carriage,  and 
C  the  compound  rest.  The  curved 
bar  D  is  attached  to  the  bed  by 
means  of  suitable  brackets  at  each  end,  as  shown  in  Fig.  157. 
This  bar  is  made  exactly  to  the  curve  which  the  rolls  are  to  have, 
both  on  its  concave  and  its  convex  edges,  and  serves  as  a  guide 
for  moving  the  compound  rest  forward  and  back  so  as  to  produce 
the  proper  curve  in  its  travel  across  the  work. 


FIG.  155.  —  Forms  of  Convex  and 
Concave  Rolls  to  be  Turned. 


FIG.  156.  —  Cross  Section  of  Attachment  for  Turning  Convex 
and  Concave  Rolls". 

To  accomplish  this  travel  the  cross-feed  screw  nut  E  travels 
in  a  slot  in  the  compound  rest  and  may  be  fixed  at  any  point  therein 
by  the  screw  F.  Fixed  to  the  rear  end  of  the  compound  rest  shoe 


182 


MODERN   LATHE   PRACTICE 


C  is  a  bracket  G,  in  which  is  pivoted  the  small  friction  roller  H, 
which  bears  against  the  edge  of  the  curved  former  bar  D.  Attached 
also  to  the  compound  rest  is  the  weight  K,  by  means  of  a  cord 
which  runs  over  a  sleeve  L,  attached  to  the  lathe  carriage. 

In  the  use  of  this  device  the  clamp  screw  F  is  tightened  up  so 
as  to  fix  the  cross-feed  screw  nut  E  in  its  place  and  the  rough  forging 
for  the  roll  turned  down  nearly  to  the  finish  size  and  form  in  the 
usual  manner.  The  clamp  screw  F  is  then  loosened  and  the  fric- 


FIG.  157.  —  Plan  of  Attachment  for  Turning  Convex 
and  Concave  Rolls. 

tion  roll  H  brought  against  the  curved  guide-bar  D  by  the  weight 
K,  and  the  finishing  cuts  taken  to  the  proper  curve. 

When  the  rolls  are  to  be  made  largest  in  the  center,  the  guide- 
bar  D  is  reversed,  bringing  its  convex  side  next  to  the  friction 
roller  H. 

A  similar  attachment,  or  in  fact  this  one,  may  be  used  to  finish 
other  curves,  whether  simple  or  compound,  so  long  as  the  contour 
is  made  up  of  easy  curves  capable  of  being  followed  by  the  friction 
roller  H,  as  shown  in  the  engraving.  Small  pieces,  say  less  than 


LATHE  ATTACHMENTS 


183 


six  inches  in  length,  may  be  more  economically  finished  by  means 
of  forming  tools. 

Another  very  desirable  attachment  for  machining  concave  and 
convex  surfaces  is  of  German  origin.  Figure  158  shows  a  front 
elevation  and  Fig.  159  a  plan  of  a  lathe  fitted  with  this  attachment. 


I 

FIG.  158.  —  Front  Elevation  of  Attachment  for  Turning  Concave  Surfaces. 

It  is  very  simple  in  its  construction  and  consists  of  a  radius  bar  A, 
which  is  pivoted  at  its  rear  end  to  a  block  D,  and  at  its  front  end 
to  the  tool  block  of  the  compound  rest  at  B.  By  reference  to  the 
plan  in  Fig.  159,  it  will  be  readily  seen  that  as  the  cross-feed  is 
operated,  the  compound  rest  must  swing  upon  its  center  according 
to  the  radius  of  the  bar  A,  and  be  governed  by  it. 


FIG.  159.  —  Plan  of  Attachment  for  Turning  Concave 
Surfaces. 


It  is  necessary  for  its  practical  working  that  all  fits  and  adjust- 
ments must  be  nicely  made  and  accurately  set  in  order  to  have  this 
attachment  operative.  Also,  that  unless  the  parts  are  all  com- 
paratively heavy  and  rigid,  the  cuts  made  would  of  necessity  be 
light  ones,  otherwise  the  tool  would  be  likely  to  have  considerable 
vibration  and  leave  " chatter  marks"  in  the  work. 

It  should  also  be  remembered  that  for  a  large  radius  the  tool 


184 


MODERN  LATHE   PRACTICE 


must  project  out  farther  from  the  center  of  the  compound  rest  as 
in  other  attachments  of  the  kind,  since  the  radius  bar  has  nothing 
to  do  with  determining  or  governing  the  radius  of  the  curve 
machined. 

Figure  160  is  a  front  elevation  and  Fig.  161  a  plan  of  a  similar 


FIG.  160.  —  Front  Elevation  of  Attachment  for  Turning  Convex  Surfaces. 

attachment  to  the  above,  and  of  like  origin,  having  for  its  object 
the  machining  of  convex  surfaces.  This  is  a  more  complex  matter, 
and  the  manner  in  which  it  is  accomplished  is  at  once  ingenious  and 
practical,  and,  so  far  as  the  author  is  aware,  is  new  in  this  country. 
In  the  design  of  an  attachment  so  arranged  as  to  effect  the 
proper  movement  of  the  tool  to  produce  a  convex  curve,  tliat  is,  a 
drawing  back  of  the  cutting-tool  as  it  advances,  it  is  obvious  that 
the  length  of  the  radius  bar  must  be  the  same  as  the  radius  of  the 
curve  which  it  is  to  produce.  The  bar  A  is  made  to  this  length  and 


FIG.  161.  —  Plan  of  Attachment  for  Turning  Convex  Surfaces. 

is  pivoted  at  I  to  a  slide  K,  free  to  move  longitudinally  on  the  lathe 
bed.  The  other  end  of  the  bar  A  is  pivoted  to  a  cross-slide  F, 
which  moves  on  a  guide  E,  rigidly  secured  to  the  lathe  bed.  The 
carriage  cross-slide  has  attached  to  it  the  roller  G,  which  engages 
jaws  in  the  slide  F,  and  hence,  as  it  is  fed  across  the  surface  of  the 


LATHE  ATTACHMENTS  185 

work,  the  slide  F  is  carried  along  with  the  carnage  cross-slide.  The 
resultant  effect  of  the  movement  of  the  bar  A  is  to  move  the  block 
K  along  the  lathe  bed,  and  this  movement  is  transmitted  to  the 
carriage  by  means  of  the  connecting  bar  L,  this  compound  move- 
ment causing  the  point  of  the  tool  to  describe  an  arc  of  which  the 
length  of  the  bar  A  is  the  radius. 

In  this  device,  also,  it  is  necessary  to  have  all  the  parts  strong 
and  rigid,  with  bars,  studs,  bolts,  etc.,  much  larger  and  of  better 
mechanical  construction  than  those  shown  in  the  engraving,  in 
order  to  insure  accurate  and  well  finished  work  as  well  that  which 
will  be  economical  in  point  of  the  time  required  to  perform  it. 

In  making  cutters  for  use  in  milling  machines,  gear  cutters  and 
the  like,  it  is  not  sufficient  that  the  correct  form  be  given  to  the 
face  or  cutting  edge  of  the  teeth  only.  This  form  must  be  carried 
on  to  the  back  of  the  teeth  so  that  in  grinding  the  face  of  the  teeth, 
when  they  have  become  dulled  from  use,  they  will  still  maintain 
their  original  and  correct  form. 

This  would  be  a  simple  matter  and  might  be  readily  accom- 
plished in  forming  up  the  blank  in  the  lathe  previous  to  cutting 
the  teeth,  if  it  were  not  for  the  fact  that  there  must  be  some  "side 
clearance"  allowed  to  the  teeth.  In  other  words,  the  teeth  must 
be  widest  and  the  diameter  of  the  cutter  the  largest  across  the 
cutting  edge  and  the  points  of  the  teeth  respectively,  and  the  "form" 
carried  back  from  this  in  a  decreasing  radius. 

This  form  is  produced  by  the  process  known  by  the  technical 
term  of  "backing  off." 

There  are  various  attachments  in  the  market  for  performing 
this  operation.  The  conditions  of  the  case  require  that  for  each 
tooth  of  the  cutter  the  forming  tool  must  commence  to  cut 
at  the  cutting  edge  of  the  cutter,  quickly  move  in  toward  the  center 
until  the  cutting  edge  of  the  next  tooth  approaches,  then  fly  back 
to  the  original  position  ready  for  cutting  the  next  tooth.  This 
motion  is  repeated  for  each  tooth,  and  the  tool-holding  device  must 
be  likewise  capable  of  being  constantly  adjusted  to  the  depth  of 
the  cut  as  the  metal  is  cut  away  so  as  to  reduce  it  until  the  cut 
comes  quite  near  the  cutting  edge. 

From  these  conditions  it  will  be  seen  that  there  must  be  a  quick 
advance  and  an  instantaneous  return  of  the  forming  tool  for  each 


186 


MODERN  LATHE  PRACTICE 


tooth  of  the  cutter.    To  produce  this  movement  is  the  function 
of  the  "backing-off"  or  "relieving"  attachment. 

An  ingenious  device  of  this  kind  is  illustrated  in  Figs.  162,  163, 
and  164,  of  which  Fig.  162  is  a  plan  of  the  attachment,  Fig.  163 


G  j  F 


FIG.  162.  —  Attachment  for  "Backing-off"  or 
"Relieving"  the  Teeth  of  Cutters. 

shows  one  of  the  actuating  cams,  and  Fig.  164  .shows  the  bracket 
and  friction  roller  that  rests  against  the  actuating  cam  shown 
in  Fig.  163. 

The  construction  of  the  device  is  as  follows:  Upon  the  small 
face-plate  A  of  the  lathe  is  fixed  the  actuating  cam  B,  shown  in  Fig. 
163.  Upon  the  swivel  bar  of  a  regular  taper  attachment  C  is  fixed 
the  bracket  D,  in  the  upper  end  of  which  is  journaled  the  friction 

/f 


FIG.  163.  — 
Ratchet  Cam 
for  "Backing- 
off"  Attach- 
ment. 


FIG.  164. —  Brac- 
ket for  Cam  Rol- 
ler of  "Backing- 
off ' '  Attachment. 


roller  E,  which  bears  against  the  actuating  cam  B.  The  swivel  bar 
is  pivoted  at  F,  as  usual,  and  when  used  for  the  purposes  of  this 
attachment  the  clamping  screws  at  either  end  (not  shown)  are  left 
slightly  loose  so  as  to  permit  it  to  swivel  slightly,  and  the  friction 
roller  E  held  tightly  against  the  actuating  cam  B  by  means  of  a 
strong  spring  at  H.  K  is  the  cutter  to  be  "backed  off,"  and  L  is 
the  forming  tool  doing  the  work. 

The  compound  rest,  or  cross-slide,  as  the  case  may  be,  is  con- 
nected to  the  taper  attachment  sliding  block  J  by  a  pivot  bolt  G, 
in  the  usual  manner. 


LATHE  ATTACHMENTS 


187 


The  operation  of  the  device  is  this.  The  swivel  bar  of  the  taper 
attachment  forms  a  lever  by  which  the  motion  derived  from  the 
actuating  cam  B  is  conveyed  to  the  tool-holding  device  of  the  com- 
pound rest,  the  forming 
tool  being  drawn  in  as  the 
friction  roll  E  rides  up  on 
the  cam  tooth,  and  suddenly 
dropping  back  to  its  original 
position  as  the  roller  drops 
off  the  point  of  the  cam 
tooth,  the  actuating  cam 
always  revolving  in  the  di- 
rection indicated  by  the  ar- 
row. 

There  are  two  impor- 
tant advantages  possessed 
by  this  arrangement.  First, 
it  is  very  economically  and 
conveniently  applied  to  an 
engine  lathe  having  a  taper 
attachment.  Second,  as  the  taper  attachment  swivel  bar  is  used 
as  a  lever  in  obtaining  the  motion  desired,  this  leverage  may  be 
as  small  or  as  great  as  desired  by  bringing  the  pivot  bolts  F  and 
G  nearer  together  or  farther  apart.  Thus  the  amount  of  "clear- 
ance" given  to  the  teeth 
of  the  cutter  is  entirely 
under  the  control  of  the 
operator,  who  can  change 
or  modify  this  condition 
at  any  time,  even  while 
the  work  is  in  progress,  by 
simply  moving  the  taper- 
attachment  brackets  to 
the  right  or  left  on  the 
lathe  bed. 

In  Fig.  165  is  shown  the  plan,  and  in  Fig.  166  the  elevation, 
of  a  convenient  and  practical  stop  for  the  cross-feed  of  an  engine 
lathe.  It  is  not  only  very  useful  in  thread  cutting  but  in  getting 


FIG.  165.  —  Plan  of  Micrometer  Stop  Attach- 
ment for  Cross-Feed  of  Lathes. 


FIG.  166.  —  Front  Elevation  of  Micrometer 
Stop  Attachment  for  Cross-Feed  of  Lathes. 


188  MODERN   LATHE   PRACTICE 

accurate  dimensions  of  both  inside  and  outside  work,  as  well  as  to 
accurately  turn  different  diameters  with  the  same  tool  and  at  the 
same  setting. 

The  construction  of  the  device  is  as  follows:  Upon  the  cross-, 
slide  A  is  fitted  the  cross-feed  stop  B,  constructed  as  usual. 
Through  this  piece  and  into  the  tool  block  C  passes  the  stop  stud 

D,  being  fixed  in  the  latter  piece.     This  stud  is  threaded  20  to 
the  inch,  and  the  micrometer  nuts  E,  E,  graduated  in  50  spaces, 
thus  giving  a  reading  of  .001,  upon  which  quarter  thousands  may 
be  easily  determined. 

The  micrometer  nuts  are  recessed  on  the  side  next  to  the  feed 
stop  B,  and  provided  with  a  washer  and  short  spiral  spring.  The 
washer  is  prevented  from  turning  except  with  the  nut  by  a  small 
pin  in  the  nut  and  fitting  in  a  suitable  notch  in  the  edge  of  the 
washer.  This  washer  is  threaded  the  same  as  the  nut  E,  and  the 
action  of  the  spring  causes  friction  enough  on  the  thread  to  prevent 
the  nut  from  turning  by  any  jar  to  which  the  lathe  may  be  sub- 
jected. This  construction  also  excludes  dirt  and  takes  up  wear 
when  the  device  has  been  in  use  for  any  great  length  of  time. 

Two  micrometer  nuts  are  used  so  that  inside  as  well  as  outside 
work  may  be  accurately  turned. 

When  different  diameters  are  to  be  turned,  stop  levers  of  vary- 
ing thickness,  one  of  which  is  shown  at  F,  are  used  by  placing  them 
on  the  stud  G,  and  secured  by  the  nut  H  and  its  spiral  spring. 
This  stop  must,  of  course,  be  exactly  one  half  the  difference  between 
the  large  and  the  small  diameter  in  thickness.  In  use  it  is  turned 
down  so  as  to  come  between  the  stop  B  and  the  micrometer  nut 

E.  When  not  in  use  it  is  turned  over  against  the  pin  J.    Two  or 
more  of  these  stops  may  be  used  without  removing  either  of  them, 
provided  the  one  next  to  the  stop  B  is  used  first  and  the  others 
added  successively  to  it,  or  vice  versa. 

While  such  an  attachment  as  the  one  here  shown  is  a  valuable 
aid  to  a  careful  operator,  it  is  not  an  assurance  that  accurate  diam- 
eters will  be  continuously  turned  out  when  the  operator  becomes 
careless  and  "runs  hard  against  the  stop,"  or  is  guilty  of  the  oppo- 
site error  of  not  coming  closely  up  to  it.  Both  these  errors  have 
caused  a  great  deal  of  trouble  to  shop  foremen. 

In  these  modern  days  and  days  of  modern  methods,  when  me- 


LATHE  ATTACHMENTS  189 

chanical  accuracy  is  the  great  desideratum,  the  subject  of  grinding 
cylindrical  surfaces  has  absorbed  a  great  deal  of  attention.  It  was 
long  ago  realized  that  it  was  next  to  impossible  to  construct  a  lathe 
so  accurate  that  it  was  possible  to  turn  a  perfectly  cylindrical  piece 
of  work  upon  it. 

Grinding  was  formerly  used  principally  in  the  construction  of 
gages  of  various  forms,  but  particularly  cylindrical  gages.  As 
grinding  machines  were  simplified  and  improved  it  was  found  that 
the  grinding  processes  were  continually  becoming  more  economical, 
and  that  therefore  the  extreme  accuracy  which  such  processes  made 
possible  could  be  applied  to  many  other  kinds  or  classes  of  work. 

Grinding  as  performed  in  an  engine  lathe  was  accomplished  by 
a  " home-made"  grinding  attachment,  more  or  less  crude,  and  bolted 
down  to  the  lathe  carriage,  tool  block,  or  compound  rest.  The 
spindle  carried  a  grooved  pulley  from  which  a  round  leather  belt 
went  up  to  a  wooden  drum  hung  up  over  the  lathe  and  driven  by  a 
short  belt  from  the  lathe  countershaft.  This  drum  was  as  long  as 
any  grinding  job  was  expected  to  be,  since  the  round  belt  must 
needs  travel  to  and  fro  upon  it  as  the  lathe  carriage  carried  the 
grinding  attachments  over  the  length  of  the  piece  of  work  to  be 
ground. 

It  must  be  admitted  that  even  with  these  crude  devices  much 
good  work  was  accom- 
plished, and  that  the  way 
was  thus  opened  for  the 
much  better  work  that 
followed  later  on. 

With  the  introduction 
of  electrical  power  and 
the  ease  with  which 
small  and  compact  mo- 
tors could  be  constructed,  FIG.  167.  —  Tool-Post  Grinding  Attachment, 
the  convenience  of  driv-  made  by  Cincinnati  Electric  Tool  Company. 

ing  grinding  devices  was  much  increased  and  the  old  overhead 
wooden  drum  is  fast  becoming  a  thing  of  the  past. 

In  Fig.  167  is  given  a  view  of  one  of  the  electrically  driven  lathe 
grinder  attachments  made  by  the  Cincinnati  Electrical  Tool  Com- 
pany. It  may  be  held  in  the  tool-post  or  tool-clamping  device,  and 


190 


MODERN  LATHE   PRACTICE 


is  entirely  self-contained,  the  emery  wheel  being  attached  to  the 
shaft  of  the  small  electric  motor  within  the  metallic  case.  It  is 
driven  by  the  current  coming  through  an  ordinary  incandescent 
lamp  cord.  Its  movements  are  regulated  by  the  crank  seen  in 
front  of  the  case,  as  well  as  by  the  cross  and  lateral  feeding 
mechanism  of  the  lathe. 

Its  compact  form,  portability,  and  the  convenience  of  attach- 
ing, using,  and  detaching,  render  it  a  very  useful  lathe  grinder.  It 
can  be  set  at  any  angle  so  as  to  grind  taper  work  as  well  as  straight, 
and  the  centers  of  the  lathe  in  which  it  is  used. 

Figure  168  is  of  a  center-grinding  attachment  made  by  the 


FIG.  168.  —  Lathe  Center  Grinding  Attachment,  made 
by  the  Hisey-Wolf  Machine  Company. 

Hisey-Wolf  Machine  Company,  and  is  shown  attached  to  a  lathe 
in  the  proper  position  for  grinding  the  head-stock  center.  Like 
the  last  example  it  consists  of  an  electric  motor  whose  shaft  carries 
the  emery  wheel.  The  shaft  is  arranged  to  travel  endwise  as  is 
necessary  in  center  grinding,  and  is  operated  by  means  of  the  double 
crank  shown  at  the  left.  It  is  driven  by  the  current  from  an  ordi- 
nary lamp  cord. 

Figure  169  represents  a  larger  grinding  attachment  made  by  the 
same  company  and  designed  for  larger  and  heavier  work  than  either 
of  the  above  devices.  It  is  arranged  to  be  bolted  down  upon  the 
lathe  carriage,  or  a  block  attached  to  it  so  as  to  bring  its  center  at 
the  same  height  as  that  of  the  center  line  of  the  lathe.  It  is  driven 
in  the  same  manner  as  the  last  two  devices. 


LATHE  ATTACHMENTS 


191 


The  entire  motor  and  case  is  attached  to  a  square  block  having 
a  vertically  sliding  surface  planed  upon  it,  and  fitting  the  bolting- 
down  and  supporting  bracket  upon  which  it  slides  vertically,  being 
adjusted  as  to  height  and  held  in  any  desired  position  by  the  double 
crank  seen  at  the  top. 

By  extending  the  shafts  of  these  motors,  either  temporarily 
or  by  having  them  so  constructed  when  built,  to  the  proper  distance 
so  as  to  carry  the  emery  wheel  at  a  considerable  distance  from  the 
motor,  they  may  be  used  for  grinding  the  inside  of  cylindrical  work, 
the  longitudinal  feed  of  the  lathe  being  made  use  of  to  give  the 
required  travel  for  the  wheel. 


FIG.  169.  —  A  Larger  Lathe  Grinding  Attachment, 
made  by  the  Hisey-Wolf  Machine  Company. 

Should  the  inside  work  be  conical  it  is  entirely  practical  to 
attach  the  grinder  to  the  compound  rest,  set  at  the  proper  angle  and 
the  wheel  fed  back  and  forth  quite  as  readily  as  on  straight  work. 

Being  electrically  driven  the  device  may  be  set  with  its  shaft  at 
right  angles  to  the  center  line  of  the  lathe,  and  face  grinding  may 
be  conveniently  performed. 

In  fact  there  are  hardly  any  of  the  ordinary  grinding  operations 
that  are  required  to  be  done  on  centers  that  may  not  be  performed 
by  one  of  these  grinders,  even  to  cutters,  reamers,  and  the  like,  by  a 
little  ingenuity  in  arranging  for  them. 

These  points  make  such  grinders  of  a  great  deal  of  value  in 
ordinary  machine  shops  and  manufactories,  and  almost  indispen- 
sable in  the  smaller  shops  where  it  is  not  always  possible  to  get  a 
regular  grinding  machine. 


192 


MODERN   LATHE   PRACTICE 


The  Rivett-Dock  thread-cutting  attachment,  shown  in  Fig. 
170,  may  with  propriety  be  classed  as  a  tool,  but  from  its  impor- 
tance in  design,  use,  and  effect  it  seems  to  deserve  being  classed  as 
an  attachment  and  so  it  is  made  a  part  of  this  chapter. 

Its  construction  and  operation  is  as  follows :  The  angle  plate  A 
is  adapted  to  be  bolted  down  on  the  tool  block  of  the  lathe,  and 
upon  its  upright  face  is  fitted  the  horizontal  slide  B,  which  may  be 
moved  forward  and  back  by  means  of  the  lever  C.  The  slide  B  has 
pivoted  to  it  the  circular  cutter  D,  whose  ten  teeth  are  shaped  in  the 


FIG.  170.  —  The  Rivett-Dock  Thread  Cutting 
Attachment. 

form  of  the  thread.  However,  the  full  form  of  the  thread  is  only 
given  by  the  last  one  used  in  cutting  the  thread,  the  others  being 
gradually  cut  away  so  that  the  first  one  hardly  more  than  marks 
the  location  of  the  cut,  the  design  being  to  cut  the  full  thread  at 
ten  cuts,  each  successive  tooth  of  the  cutter  cutting  a  little  deeper 
until  the  tenth  tooth  shall  have  but  a  trifle  to  cut  to  finish  the 
thread. 

It  will  be  noticed  that  the  tooth  marked  0  in  the  engraving 
rests  upon  a  projection  E,  which  supports  it  in  its  cutting  position 
to  act  upon  the  piece  F  which  is  being  cut.  The  cutter  having 
made  one  cut  is  withdrawn  from  contact  with  the  work  by  the 


LATHE  ATTACHMENTS  193 

handle  C,  by  which  motion  the  pawl  G,  pivoted  at  the  top  of  the 
angle  plate  A,  engages  in  the  space  between  the  teeth  of  the  cutter 
D,  and  causes  it  to  rotate  to  the  left  just  far  enough  to  bring  the 
next  tooth  into  the  cutting  position.  The  withdrawal  of  the  cutter 
from  the  support  E  permits  its  revolution.  The  cutter  is  then 
thrown  forward  and  the  next  tooth  is  ready  for  the  cut.  This 
operation  is  repeated  until  all  the  teeth  have  been  brought  into  the 
cutting  position  and  made  their  cut  in  succession,  and  the  thread  is 
completed. 

The  important  point  accomplished  by  this  device  is  that  as 
there  should  be  ten  cuts  made  to  complete  a  thread,  the  keen  edge 
of  the  tool  for  finishing  is  liable  to  be  lost  in  the  earlier  roughing 
cuts.  With  this  device  the  roughing  cuts  are  made  with  teeth 
designed  for  that  work  particularly,  and  the  thread  is  brought  to  a 
state  of  completion  by  what  is  practically  ten  different  tools. 
Hence  a  saving  of  time,  both  in  cutting  and  in  grinding  tools,  and  the 
production  of  a  smooth,  accurately  finished,  and  perfect  thread. 


CHAPTER  X 

RAPID   CHANGE   GEAR   MECHANISMS 

What  a  rapid  change  gear  device  is.  The  old  pin  wheel  and  lantern  pinion 
.  device.  The  first  patent  for  a  rapid  change  gear  device.  The  inven- 
tors' claims.  Classification  of  rapid  change  gear  devices.  The 
inventors  of  rapid  change  gear  devices.  Paulson's  originality. 
"Change  gear  devices"  by  the  author.  Le  Blond's  quick  change  gear 
device.  The  Springfield  rapid  change  gear  attachment.  Criticism  of 
the  device.  The  Bradford  rapid  change  gear  device.  Judd's  quick 
change  gear  device.  Newton's  quick  change  gear  device.  The  Flather 
quick  change  gear  device. 

BY  the  term  "rapid  change  gear"  we  understand  that  the  mech- 
anism so  denominated  is  one  capable  of  performing  all  the  func- 
tions of  the  former  change-gears  but  without  the  necessity  for 
exchanging  one  gear  for  another  or  one  set  of  gears  for  another, 
that  is,  without  removing  a  gear. 

These  gears  were  formerly  called  ' 'change-gears"  because  they 
were  subject  to  change  for  each  new  operation  of  the  lathe  in  which 
their  use  was  essential. 

In  the  old-fashioned  "  chain  lathe,"  having  a  lead  screw  driven 
by  "pin  wheels"  and  "  Ian  tern  pinions,"  which  is  illustrated  and 
described  in  Chapter  II,  it  will  be  seen  that  the  builder  had  pro- 
vided for  changing  the  pitch  of  the  thread  to  be  cut  by  changing 
only  one  gear.  This  was  about  the  year  1830.  In  1882,  George  A. 
Gray,  Jr.,  obtained  a  patent,  No.  252,760,  for  a  change  gear  arrange- 
ment whose  principal  feature  was  that  only  one  gear  need  be  re- 
moved and  changed  to  cut  any  of  the  usual  threads. 

The  first  effort  in  the  direction  of  devising  a  rapid  change  gear 
mechanism  was,  so  far  as  the  United  States  Patent  Office  is  con- 
cerned, made  by  Edward  Bancroft  and  William  Sellers,  who  on 
February  7,  1854,  obtained  Patent  No.  10,491,  for  a  device  con- 

194 


RAPID   CHANGE   GEAR  MECHANISMS  195 

sisting  of  two  cones  of  gears  intermeshing,  one  set  fast  to  the  shaft 
and  the  other  set  adapted  to  fix  any  single  gear  to  the  shaft  by 
means  of  a  pin  passing  through  a  fixed  flange  and  into  a  hole  in 
a  gear  or  the  hub  of  a  gear;  the  set  being  made  with  telescoping 
hubs,  the  ends  of  all  coming  against  the  fixed  plate.  It  is  interest- 
ing, in  the  light  of  present  developments  in  this  line,  to  read  the 
first  claim  of  their  patent,  so  prophetic  of  the  developments  to  come, 
as  follows:  "The  method  of  varying  the  motions  of  the  mandrel  or 
screw-shaft,  or  leader,  by  means  of  two  series  of  wheels  of  different 
diameters,  and  all  of  the  wheels  of  one  series  being  connected  and 
turning  together,  and  imparting  motion  to  all  the  wheels  of  the 
second  series  with  different  degrees  of  velocity,  substantially  as 
described." 

While  a  number  of  the  later  inventors  claimed  these  same 
features  of  the  mechanism  and  apparently  considered  themselves 
as  the  original  inventors,  it  will  be  readily  seen  that  the  mechanical 
ideas  involved  in  this  invention  anticipated  their  claims  by  a  goodly 
number  of  years. 

In  considering  the  question  of  rapid  change  gear  devices  it  .will 
be  well  to  adopt  fome  classification  based  upon  their  design  or 
structural  differences.  We  may  then  illustrate  and  describe  these 
general  classes  by  well-known  or  readily  understood  examples, 
whereby  all  devices  of  this  kind  may  be  more  easily  understood  and 
their  special  features  appreciated  at  their  proper  value. 

Thus  we  may  classify  these  devices  in  their  general  groups  as 
follows : 

First,  those  in  which  the  gears  representing  the  former  change- 
gears  are  all  placed  on  one  shaft; 

Second,  those  in  which  these  gears  wrere  placed  on  several 
shafts  or  studs,  and  arranged  in  a  circle ;  and 

Third,  those  in  which  neither  of  these  arrangements  existed. 

Of  the  first  class,  using  what  has  become  well  known  as  the 
"cone  of  gears,"  the  most  notable  inventors  are  Bancroft  and 
Sellers,  Humphreys,  Miles,  Riley,  Hyde,  Joseph  Flather,  Peter  and 
William  Shellenback,  Norton,  William  Shellenback,  Herbert  L. 
Flather,  Ernest  J  Flather,  Wheeler,  Isler,  Le  Blond,  Johnson  and 
Wood. 

Of  this  number  it  was  usual  to  use  one  or  two  cones  of  gears, 


196  MODERN   LATHE  PRACTICE 

but  this  number  did  not  seem  to  satisfy  the  ambition  of  some  of  the 
inventors,  since  one  of  them,  Isler,  used  no  less  than  six  cones  of 
gears.  Usually  these  cones  of  gears  were  located  under  the  head 
or  in  front  of  it,  but  sometimes  within  the  bed.  But  Johnson, 
apparently  being  determined  to  have  a  cone  of  gears  somewhere, 
places  them  on  a  loose  sleeve  running  on  the  main  spindle.  It 
remained  for  Wheeler  to  find  a  new  location  for  his  cone  of  gears  by 
placing  them  in  the  apron. 

Among  all  these  devices,  as  in  other  spheres  of  mechanical 
effort,  the  inventors  produced  mechanisms  ranging  all  the  way  from 
"good  and  bad,  to  indifferent." 

Of  the  second  class,  that  is,  those  who  located  the  gears  on  short 
shafts  arranged  in  a  circle,  the  first  to  devise  this  arrangement  was 
Edward  Flather,  who  obtained  patent  No.  536,615,  on  April  2, 
1895,  and  was  later  followed  by  Benj.  F.  Burdick,  William  L. 
Shellenback,  Edward  A.  Muller,  and  Herman  R.  Isler,  in  the  order 
named,  the  latter 's  last  patent  having  been  granted  in  1902. 

Of  the  exceptional  examples,  included  in  class  third,  the  most 
notable  one  is  the  invention  of  Carl  J.  Paulson,  who  adopted 
the  very  original  method  of  making  a  series  of  rings  fitting  inside 
each  other,  cutting  gear  teeth  on  a  portion  of  the  face  of  each  and 
arranging  the  proper  mechanism  to  thrust  out  from  its  fellows,  the 
gear  having  the  desired  number  of  teeth  that  might  be  needed. 
This  was  probably  the  most  original  of  all  the  methods  employed 
up  to  the  present  time. 

While  this  device  was  not  a  commercial  success,  it  had  a  counter- 
part and  was  the  prototype  of  a  quite  similar  arrangement  consist- 
ing of  two  sets  of  sleeves  in  line  with  each  other  and  having  teeth 
cut  on  their  outer  surfaces  precisely  as  Paulson  had  done,  and 
arranging  them  and  their  connecting  gears  in  a  more  practical  and 
operative  combination. 

An  interesting  review  might  be  written  and  illustrated  of  the 
various  patented  change  gear  mechanisms  that  have  been  invented 
since  the  days  of  Bancroft  and  Sellers,  but  it  is  hardly  within  the 
scope  of  this  work  to  give  the  necessary  space  to  this  portion  of 
lathe  description.  If  the  reader  desires  to  pursue  the  subject  in 
detail  and  to  have  dates,  patent  numbers,  and  illustrations  from  the 
drawings  in  the  patent  office,  he  is  referred  to  a  book  by  the  author 


RAPID  CHANGE  GEAR  MECHANISMS 


197 


entitled  " Change  Gear  Devices,"  wherein  all  this  data  is  presented 
in  detail. 

For  the  purposes  of  this  work  it  will  be  sufficient  to  present  a  few 
of  the  more  recent  examples  in  this  chapter  and  to  call  attention  to 
the  engravings  of  a  number  of  others  in  other  chapters  wherein  the 
lathes  of  prominent  builders  are  illustrated  and  the  change  gear 
devices  shown.  Among  these  are  the  lathes  built  by  Hamilton 
Machine  Tool  Company,  Bradford  Machine  Tool  Company,  Hendey 
Machine  Tool  Company,  Prentice  Brothers  Company,  Springfield 
Machine  Company,  etc. 


FIG.  171.  —  End  Elevation  of  Le  Blond's  Quick  Change  Gear  Device. 

The  quick  change  gear  device  designed  by  R.  K.  Le  Blond  is  an 
interesting  example  of  this  type  of  mechanism.  Figure  171  shows 
an  end  elevation  of  this  lathe,  and  Figs.  172,  173,  and  174  some  of 
the  details  of  the  gearing. 

The  lathe,  with  the  exception  of  these  features,  is  the  same  as 
the  standard  engine  lathe  built  by  this  company,  and  the  head- 
stock  end  is  shown  in  Fig.  171,  which  gives  a  good  idea  of  the 
exterior  appearance  of  the  change  gear  device. 


198 


MODERN   LATHE   PRACTICE 


FIG.  1,72.  —  Sectional  View  of 
Le  Blond's  Quick  Change 
Gear  Device. 


The  line  drawing,  Fig.  172,  shows  the  connection  between  the 
feed  box  and  the  lathe  spindle.  The  spindle  gear  A  drives  gear  D 
on  the  stud  D1;  through  tumbler  gears  B  and  C.  The  tumbler  gears 

are  of  the  regular  construction  used  for 
reversing  the  motion  of  the  carriage  in 
screw  cutting,  so  as  to  cut  either  right 
or  left  hand  threads,  as  required. 

Motion  is  transmitted  from  the 
tumbler  gears  through  gears  D,  Ew  G, 
and  H,  which  latter  is  on  the  driving- 
shaft  of  the  feed  box.  In  order,  how- 
ever, to  obtain  a  second  series  of  feeds 
there  is  a  telescopic  slip  gear  located 
on  the  stud  D1  which  can  be  made  to 
mesh  with  gear  G  in  place  of  pinion  ^ 
which  is  shown  in  mesh  with  gear  G  in  the  engraving.  To  accom- 
plish this,  G  rotates  on  a  pin  in  a  quadrant  Gt,  which,  by  means  of 
the  clamping  handle  G4  and  the  stops  G2  and  G3  can  be  brought 
into  the  correct  position  for  gear  G  to  mesh  either  with  pinion  Et 
or  gear  F,  as  required.  The  hub  of  gear  F  is  recessed  so  that  it  can 
be  slid  over  pinion  Ex,  thus  bringing  this  gear  in  the  same  plane 
with  gear  G.  Gears  D  and  F  and  the  pinion  Ex  all  rotate  with  the 
stud,  which  is  journaled  in  a  bearing  in  the  head-stock  casting. 
The  introduction  of  the  telescopic  gear  F  makes  a  change  in  the 
feed  ratio  of  4  to  1. 

Figure  173  is  reproduced  from  the  patent  specification  and 
shows  clearly  the  mechanism  of  the  feed  box.  A  is  the  driving  shaft 
and  B  the  driven  shaft,  which  in  this  case  is  represented  as  being 
one  end  of  the  lead  screw,  but  in  the  actual  lathe  is  connected  with 
the  latter  by  suitable  intermediate  gearing.  However,  the  prin- 
ciple of  the  feed  changes  is  the  same  in  either  case.  Shaft  B  carries 
a  cone  of  gears  and  shaft  A  an  elongated  spur  gear  C,  which  is  the 
driving  gear  of  the  mechanism. 

Surrounding  this  elongated  gear  C  is  a  cylindrical  barrel  D, 
which  serves  the  double  purpose  of  a  casing  for  the  gear  and  a 
bearing  for  a  sliding  bushing  E,  by  means  of  which  the  adjustment 
of  feed  is  effected.  This  bushing  carries  at  F  an  intermediate 
gear  which  at  all  times  is  in  mesh  with  gear  C  and  can  also  be  brought 


RAPID   CHANGE   GEAR  MECHANISMS 


199 


into  mesh  with  one  of  the  gears  in  the  cone  by  giving  the  bushing  E 
a  combined  sliding  and  rotary  motion  on  the  barrel  D. 

The  portion  of  the  barrel  D  which  is  toward  the  cone  of  gears  is 
provided  with  a  longitudinal  slot,  to  allow  the  intermediate  gear 
F  to  project  through  and  mesh  with  gear  C.  The  front  portion  of 
the  barrel  is  provided  with  a  series  of  holes,  corresponding  in  num- 
ber and  position  to  the  gears  of  the  cone,  so  that  the  bushing  which 


EXTERIOR  VIEW 

FIG.  173.  —  Details  of  Le  Blond's  Quick  Change 
Gear  Device. 

carries  the  intermediate  gear  F  can  be  locked  in  its  proper  position 
for  each  gear  by  means  of  a  spring  pin,  after  the  usual  manner. 
The  bushing  which  acts  as  carrier  for  the  gear,  and  the  barrel  which 
encases  the  elongated  gear,  are  clearly  represented  in  the  detailed 
view  of  the  mechanism,  Fig.  173. 

Figure  174  is  a  view  looking  at  rear  of  the  mechanism  and  its 
casing,  and  shows  the  modifications  that  have  been  made  in  the 
device  to  adapt  it  to  the  engine  lathe.  The  cone  shaft  carries  be- 
sides the  eight  gears  of  the  cone,  an  additional  gear,  K,  and  below 
this  shaft,  which  is  marked  B,  is  the  shaft  L,  which  is  connected 
directly  to  the  feed  rod  R,  and  carries  a  sliding  sleeve  S,  on  which 
are  two  pinions,  M  and  N. 


200 


MODERN   LATHE   PRACTICE 


In  the  position  shown  in  this  view  power  is  transmitted  from 
the  cone  shaft  B  to  the  gear  N  by  means  of  the  auxiliary  pinion  K, 
and  as  the  sleeve  S  is  splined  to  shaft  L  the  motion  is  transmitted 
to  this  shaft  and  thence  to  the  feed  rod.  By  sliding  the  sleeve  to 
the  right,  gear  N  no  longer  meshes  with  pinion  K,  but  instead  pinion 
M  meshes  with  one  of  the  gears  of  the  cone,  causing  the  feed  rod 
to  rotate  at  a  faster  speed.  The  lead  screw  T  is  driven  from  the 
feed  rod  by  a  slip  gear  W,  in  the  usual  manner. 

From  the  above  description  it  will  be  seen  that  with  the*  gear 
box  itself  eight  changes  of  feed  are  obtained.  The  slip  gear  on  the 
auxiliary  shaft  in  the  feed  box  makes  16  changes,  and  these  16 
changes  are  again  doubled  by  the  telescopic  gear  on  stud  Dl;  in 


FIG.  174  — .  Rear  View  of  Le  Blond's  Quick  Change  Gear  Device. 

Fig.  2,  making  32  changes  and  giving  a  range  of  threads  from  3  to 
46  per  inch,  covering  every  standard  thread,  including  11J. 

This  entire  range  of  threads  can  be  made  without  stopping  the 
lathe  or  removing  a  single  gear.  The  feeds  are  four  times  the  num- 
ber of  threads  per  inch.  It  will  be  noticed  that  the  compounding 
generally  adopted  on  this  style  of  lathe  is  done  away  with,  and  that 
wherever  there  are  coarse  feeds  or  heavy  threads  the  increase  comes 
directly  from  the  4  to  1  gear  on  the  stud  D17  speeding  up  the 
feed  mechanism  of  the  feed  box  in  the  same  proportion,  so  that  it 
is  placed  under  no  additional  strain. 

Figures  175  and  176  illustrate  the  "rapid  change  gear  at- 
tachment" of  the  Springfield  Machine  Tool  Company's  "Ideal" 
lathe.  They  make  use  of  the  design  placed  in  the  second  class, 


RAPID  CHANGE  GEAR  MECHANISMS  201 

that  is,  those  which  have  their  change-gears  mounted  upon  studs 
or  short  shafts  arranged  in  a  circle. 

The  change-gears  are  mounted  in  a  gear  box,  shown  at  the  left- 
hand  side  of  the  engraving,  Fig.  175,  the  intermediate  and  head- 
stock  spindle  gears  being  those  ordinarily  used.  The  cover  of  the 
gear  box  is  rotated  about  a  central  stud,  and  the  gears  are  carried 


FIG.  175.  —  Rapid  Change  Gear  Attachment  built  by  the 
Springfield  Machine  Tool  Company. 

on  the  inside  of  the  cover,  arranged  in  a  circle  concentric  with  the 
case,  and  this  circle  brings  the  change-gears  opposite  the  end  of  the 
lead  screw  by  revolving  the  cover  of  the  case. 

Referring  to  Fig.  176,  the  small  clutch  C  moves  a  telescopic 
extension  of  the  lead  screw  and  enters  it  into  a  hole  in  the  change- 
gear  before  the  driving  clutches  between  the  change-gear  and  the 
extension  come  into  contact.  This  device  takes  the  bearing  of 
the  change-gear  upon  the  extension  for  its  support,  and  secures  the 
change-gear  to  the  lead  screw  as  firmly  as  if  fastened  by  a  nut.  In 
order  to  change  the  gear,  the  cover  is  revolved  until  the  desired 


202 


MODERN   LATHE  PRACTICE 


gear  is  opposite  the  center  of  the  lead  screw  extension,  when  the 
small  clutch  is  thrown.  All  of  the  eight  change-gears  are  protected 
by  the  case  except  the  top  of  the  one  which  is  in  mesh  with  the 
intermediate  gear. 

To  give  a  sufficient  range  of  pitches,  a  set  of  three  pairs  of  gears  is 
provided  in  the  head-stock  to  vary  the  speed  of  the  intermediate 


FIG.  176.  —  Longitudinal  Section  of  Rapid  Change  Gear 
Attachment  built  by  the  Springfield  Machine  Tool  Company. 

gear.  These  are  housed  in  the  gear  cases  shown  at  the  extreme 
end  of  the  head-stock.  These  are  clutched  to  their  spindles  by 
slipping  them  on  until  their  clutches  engage  the  spindles,  which 
have  clutches  with  their  end  sections  reduced,  as  in  the  case  of  the 
lead  screw  shown  at  F  in  the  sectional  drawing,  Fig.  176.  These 
gears  furnish  ratios  of  from  1  to  1,  2  to  1,  and  4  to  1.  The  last 
two  may  be  reversed  and  five  speeds  may  be  given  to  the  fixed 
pinion  driving  the  intermediate  gear.  The  intermediate  gear 


RAPID  CHANGE  GEAR  MECHANISMS 


203 


revolves  on  a  fixed  stud  on  a  quadrant  to  which  the  handle  is 
attached,  and  is  removed  from  contact  by  raising  the  quadrant. 

This  lathe  has  a  range  of  threads  from  2  to  56  per  inch,  and  a 
range  of  turning  feeds  from  8  to  224  turns  per  inch,  and  all  the 
changes  for  any  of  these  feeds  or  threads  may  be  made  while  the 
lathe  is  running. 

The  objection  to  this  device  is  the  inherent  weakness  of  the 
mechanism  when  the  gears  are  arranged  upon  short  studs  or  shafts 
set  around  a  circle.  These  cased-in  gears  must  of  necessity  be 


FIG.  177.  —  End  Elevation  of  the  Bradford  Rapid 
Change  Gear  Device. 

comparatively  small  and  of  narrow  face.  The  teeth  must,  from 
the  same  conditions,  be  of  fine  pitch.  Their  support  must  be  by 
comparatively  small  shafts.  All  these  conditions  render  the 
mechanism  structurally  weak  and  less  rigid  than  such  a  device 
should  be  to  stand  the  strains  of  high-speed  steel  and  modern  cuts. 

The  Bradford  Machine  Tool  Company  build  an  ingenious 
rapid  change  gear  device  which  is  shown  in  the  accompanying 
engravings,  of  which  Fig.  177  is  a  front  elevation,  Fig.  178  an 
end  elevation,  and  Figs.  179  and  180  are  sectional  views. 

The  method  of  transmitting  motion  from  the  head  spindle  to  the 
change-gear  mechanism  will  be  readily  understood  by  reference  to 


204 


MODERN   LATHE  PRACTICE 


Figs.  178  and  179.  This  mechanism  is  contained  in  a  gear  box 
located  in  front  of  the  bed,  as  seen  in  these  two  figures.  It  contains 
at  A  a  cone  of  eight  gears  carried  on  a  shaft  for  driving  the  feed 
rod  and  screw,  and  a  sliding  gear  B,  which  acts  as  a  driver  for  the 
cone  and  may  be  dropped  into  mesh  with  any  one  of  the  eight  gears 
forming  that  member.  The  shaft-driving  gear  B  carries  loosely 
at  the  outer  end  three  gears  C,  any  one  of  which  may  be  connected 
by  a  sliding  key  to  the  shaft.  The  three  gears  are  rotated  by  gears 


FIG.  178.  —  Front  Elevation  of  the  Bradford  Rapid  Change  Gear  Device. 

mounted  freely  at  D,  the  intermediate  E  carried  on  a  long  stud  on 
quadrant  F  being  engaged  with  one  of  the  three  in  the  set  D. 

Now,  leaving  the  gears  in  the  positions  shown,  it  is  obvious  that 

by  operating  the  plunger  controlling  the  key  in  gears  C,  twenty-four 

ates  of  feed  may  be  obtained,  or  eight  for  each  gear  in  set  C.    Then, 

by  the  three  positions  for  intermediate  E,  the  number  of  feed  change 

is  increased  to  seventy-two. 

At  G  will  be  noted  a  support  for  the  driving  gear  which  is  formed 
dly  on  its  shaft.  The  bracket  G  is  bolted  to  the  quadrant  and 
the  under  part  cut  out  to  allow  the  intermediate  gear  to  mesh 


RAPID  CHANGE  GEAR  MECHANISMS 


205 


in  the  pinion,  and  as  the  bracket  turns  with  the  quadrant  it  sup- 
ports the  pinion  no  matter  which  one  of  the  three  gears  the  inter- 
mediate may  be  in  mesh  with. 

Figure  180  shows  the  quick  change  gear  cut  entirely  out,  and 
ordinary  change-gears  used.  It  shows  also  on  an  enlarged  scale  the 
plunger  and  sliding  key 
whereby  one  of  the  three 
gears  C  may  be  keyed  to  the 
shaft,  allowing  the  other  two 
to  rotate  loosely.  The 
knurled  knob  can  be  taken 
off,  allowing  a  gear  of  any 
required  size  to  be  put  on 
the  lead  screw.  The  three 
gears  are  fitted  with  tool 
steel  bushings,  hardened  and 
ground.  The  center  gear  has 
a  keyway  cut  through,  and 
each  of  the  outside  gears  a 
keyway  cut  on  one  side  only, 
allowing  the  knurled  knob 
and  plunger  to  be  pulled  in, 
out,  or  to  central  position. 
A  spring  pin  holds  the  plun- 
ger when  set. 

The  locking  device  for  the 
handle  which  controls  the 
position  of  gear  B  is  shown 
at  H,  Fig.  179,  and  consists 
of  a  shoe  with  a  semicircular 
recess  at  the  end  which  snaps  under  the  heads  of  the  locking 
screws,  each  screw  head  being  of  a  conical  form,  as  in  the  enlarged 
detail  at  P,  Fig.  180,  to  fill  a  cavity  in  the  under  side  of  the  con- 
trolling handle. 

The  screws  can  be  raised  and  lowered  to  allow  the  gear  in  the 
frame  to  mesh  correctly  with  the  gears  of  the  case,  thereby  enabling 
the  operator  to  use  gears  other  than  those  ordinarily  used,  simply 
by  adjusting  the  screws  until  the  gears  mesh  properly.  The  rela- 


SECT10N  M.N 

FIG.  179.  — Sectional  Views  of  Bradford 
Rapid  Change  Gear  Device. 


206 


MODERN   LATHE   PRACTICE 


tive  positions  of  the  eight  screws  will  be  seen  in  the  front  view  near 
A,  Fig.  178 

The  threads  cut  with  this  gear  range  from  3  to  46  per  inch,  the 
screw-cutting  feeds  being  4|  times  the  feeds  for  turning. 

The  quick  change  gear  device  shown  in  section  in  Fig.  182,  and 
in  front  elevation  in  Fig.  181,  is  the  invention  of  Joseph  Judd,  a 
draftsman  employed  by  the  New  Haven  Manufacturing  Com- 
pany. 

It  is  unique  in  that  in  all  other  efforts  at  devising  a  quick  change 
gear  mechanism  the  shafts  have  been  located  parallel  to  each  other. 


0 

SECTIONAL  VIEW 

FIG.  180.  —  Sectional  View  of  Bradford  Rapid  Change  Gear  Device. 

After  much  study  of  the  subject  in  conjunction  with  the  author,  and 
after  all  former  devices  known  in  the  patent  office  had  been  thor- 
oughly investigated  and  studied  and  their  features  carefully  classi- 
fied, after  they  had  in  fact  all  been  dissected,  as  it  were,  the  question 
of  obtaining  the  most  simple  and  direct  acting  device  was  sought 
by  the  process  of  elimination  of  the  undesirable  features  of  other 
devices,  and  Mr.  Judd  hit  upon  the  idea  of  making  the  faces  of 
the  gears  composing  the  "cone  gears"  slightly  inclined  instead 
of  straight,  and  thus  make  it  in  reality  what  it  had  been  before 
in  name,  a  veritable  cone  of  gears. 

While  this  form  is  not  theoretically  correct  the  difference  is 


RAPID   CHANGE  GEAR  MECHANISMS 


207 


very  slight  when  applied  to  a  full-sized  gear,  and  the  device  operates 
much  more  smoothly  than  many  would  suppose. 

The  device  includes  a  cone  of  gears  composed  of  seven  members 
L,  and  mounted  upon  the  lead  screw  shaft  P,  to  which  they  are 
fixed.  Above  this  cone  of  gears  is  a  pinion  B,  with  an  equally 
inclined  face,  and  mounted  upon  the  quill  G  so  that  it  can  be  moved 
longitudinally  to  permit  of  its  being  engaged  with  any  one  of  the 


FIG.  181.  —  Front  Elevation  of  Quick  Change  Gear  Device, 
built  by  the  New  Haven  Manufacturing  Company. 


seven  gears  below  it.  The  quill  or  sleeve  G  is  splined  so  that 
the  pinion  B  may  slide  upon  it,  but  must  turn  with  it,  in  order  to 
convey  motion  to  the  pinion  B.  The  quill  G  is  driven  by  the 
beveled  pinion  F  keyed  on  the  end.  The  pinion  F,  in  turn,  re- 
ceives its  motion  from  the  beveled  pinion  E,  which  is  mounted  on 
the  change-gear  shaft  D,  and  which  carries  at  its  outer  end  the 
change-gear  C.  The  shaft  H,  supporting  the  quill  G,  is  mounted 


208 


MODERN   LATHE  PRACTICE 


in  two  eccentrics  J,  J,  which  give  the  beveled  pinion  B  an  in-and- 
out  motion  relative  to  the  nest  of  gears  when  manipulated  by  the 
handle  K  for  changing  the  gear  ratio. 

The  sliding  pinion  B  is  moved  longitudinally  to  the  position 
indicated  by  the  index  plate  for  the  desired  thread  or  feed,  by  means 
of  the  knob  M,  and  after  being  engaged  with  the  'desired  gear  is 
held  in  position  by  the  pin  N.  This  pin  enters  a  hole  marked  with 
the  number  of  teeth  of  the  gear  with  which  the  pinion  is  engaged, 
being,  for  instance,  48  in  the  engraving.  This  provides  quick 
changes  by  steps  between  and  including  the  ratio  32  to  56. 

For  wider  ranges  on  the  lathes  of  32-inch  swing  and  larger,  a 
stud-plate  R  is  mounted  on  the  hub  Q  at  the  left  end  of  the  gear 
box  0,  carrying  gears  so  arranged  that  threads  from  2  to  14  may 


FIG.  182.  —  Longitudinal  Section  of  New  Haven 
Quick  Change  Gear  Device. 

be  cut,  or  feeds  from  8  to  56  obtained  without  changing  the  posi- 
tion of  the  intermediate  stud,  the  gears  being  so  porportioned  that 
as  one  is  removed  from  the  change-gear  shaft  E,  it  is  used  as  the 
intermediate  gear,  and  so  on. 

Open  washers  are  used  on  the  ends  of  the  studs  so  that  no  nuts 
have  to  be  removed,  thus  making  this  portion  of  the  change  easily 
and  quickly  effected. 

On  lathes  of  18  to  28-inch  swing,  inclusive,  four  additional 
changes  are  provided.  This  is  effected  by  adjusting  gear  A  longi- 
tudinally, permitting  it  to  be  meshed  with  either  of  the  intermediate 
gears,  the  intermediate  gear  in  this  case  being  compound;  and  by 
mounting  two  gears  at  C  on  the  change  gear  shaft. 

These  gears  are  of  different  diameters  and  both  mesh  with  the 


RAPID   CHANGE  GEAR  MECHANISMS 


209 


compound  intermediate  gear.  A  sliding  spring  key  is  provided  by 
which  either  gear  can  be  thrown  into  clutch  with  the  shaft,  thus 
giving  the  four  changes  without  changing  gears,  the  stud-plate 
having  to  be  shifted  on  its  pivot  for  two  of  the  changes. 


FIG.  183.  —  Front  Elevation  of  Newton's  Quick  Change  Gear  Device. 

This  gives  a  range  from  1  to  15  threads  per  inch  and  feeds  from 
4  to  60  per  inch  inclusive.  By  changing  gear  A,  the  other  changes, 
of  course,  are  readily  obtained. 

It  will  be  noticed  that  the  device  is  very  compact  and  very  simple, 
requiring  a  less  number  of 
gears  and  other  operative  LL 

parts  than  almost  any  de-       — 
vice  adapted  to  give  a  like 
number  of  useful  changes. 

Figure  183  is  a  front 
elevation  and  Fig.  184  a 
partial  cross  section  of  the 
quick  change  gear  device 
invented  by  Albert  E.  New- 
ton and  applied  to  the 
lathes  built  by  the  Pren- 
tice Brothers  Company. 

The  inventor  has  directed  his  efforts  to  the  production  of  an 
improved  change  speed  gearing  of  suitable  form  for  economical 
manufacture  and  installation  and  which  would  be  conveniently 
handled  to  actuate  the  feed  rod  or  the  lead  screw. 


FIG.  184.  —  Partial  Cross  Section  of  Newton's 
Quick  Change  Gear  Device. 


210  MODERN  LATHE  PRACTICE 

The  construction  and  operation  of  the  device  is  as  fol- 
lows : 

The  lathe  carriage  may  be  actuated  by  the  usual  feed  rod  A 
or  may  be  driven  by  the  lead  screw  B  when  screw  cutting.  There 
is  a  bearing  in  the  rear  end  of  the  head-stock  for  the  shaft  C  and  this 
is  driven  from  the  spindle  through  the  usual  tumbler  gears  arranged 
for  the  handy  reversal  of  the  shaft. 

There  are  three  gears  fastened  to  the  shaft  C  and  there  is  a  sweep 
D  having  a  transverse  slot  fitting  a  bolt  threaded  into  the  end  of  the 
lathe  bed.  The  sweep  or  stud-plate  can  be  turned  about  its  sup- 
porting hub  and  fixed  in  any  position  to  which  it  is  adjusted.  By 
this  means  an  intermediate  gear  can  be  put  in  mesh  with  any  two 
of  the  six  gears  shown,  and  this  forms  a  very  convenient  arrange- 
ment for  a  three-speed  connection  and  avoids  the  use  of  an  inter- 
changeable set  of  gears  at  this  point,  the  change  being  made  with 
gears  already  in  position  for  the  purpose. 

As  will  be  noticed,  the  intermediate  gear  need  be  no  greater  in 
width  than  any  of  the  six  gears  with  which  it  meshes. 

A  countershaft  E  carries  a  series  of  gears.  On  the  shaft  F  is  a 
forked  lever  G,  and  between  the  arms  of  the  latter  is  a  pinion  J  with 
a  key  engaging  the  keyway  cut  in  F.  An  intermediate  gear  in 
mesh  with  the  pinion,  is  journaled  on  the  stud  extending  between 
the  parts  of  the  forked  lever  G.  The  end  of  this  lever  is  turned 
upward  and  is  provided  with  a  handle.  A  pin  H  is  fitted  in  the 
ear  extending  from  the  lever  and  is  controlled  by  a  spring-pressed 
trigger  carried  by  the  handle. 

A  cover  plate  is  secured  to  the  bed  to  form  a  box  over  the  change- 
gears,  and  the  front  lower  edge  of  the  plate,  as  illustrated  in  Fig.  183 
has  a  guiding  rib  supporting  the  pin  H.  A  series  of  holes  is  bored 
in  the  cover  plate  and  in  line  with  the  gear-wheels.  The  forked 
lever  G  and  the  pinion  J  can  be  slid  along  the  shaft  F,  and  opposite 
the  proper  gear  the  handle  may  be  lifted  and  locked  in  place  by 
means  of  the  pin  H. 

The  end  of  the  countershaft  E  projects  through  the  right-hand 
journal  and  has  a  keyway  cut  in  it.  A  slip  pinion  K  is  fitted  on  this 
projecting  end  and  has  a  key  engaging  the  keyway.  A  gear  N  is 
on  the  end  of  the  lead  screw  B.  The  gear  L  has  a  hub  fitted  in  the 
bearing  supporting  the  left-hand  end  of  the  feed  rod  A.  The  gear 


RAPID  CHANGE  GEAR  MECHANISMS 


211 


L  is  provided  with  clutch  teeth  to  match  teeth  on  a  clutch  M  arranged 
at  the  end  of  the  rod  A. 

A  spring  normally  keeps  the  toothed  parts  in  contact.  An 
adjustable  collar  on  the  feed  rod  enables  the  carriage  to  be  auto- 
matically stopped  when  a  predetermined  point  in  the  travel  is 
reached.  The  slip  pinion  K  on  the  end  of  the  countershaft  E  can 
be  adjusted  to  engage  either  the  gear  N  on  the  lead  screw  or  the 
gear  L  that  actuates  the  feed  rod. 

The  step  gearing  on  the  countershaft  E  permits  the  same  change 
speed  gearing  to  drive  the  feed  rod  or  the  lead  screw  and  that  when 


FIG.  185.  —  Front  Elevation  of  Flather's  Quick  Change 
Gear  Device. 


either  member  is  in  use  the  other  is  idle.  The  arrangement  of  the 
countershaft  E  and  the  shaft  F  allows  them  and  their  gearing  to  be 
assembled  on  the  bench. 

The  lead  screw  and  the  feed  rod  can  be  applied  to  the  machine 
by  bolting  the  brackets  which  support  the  lathe  to  the  bed.  Then 
the  supporting  bracket  is  put  in  position  so  that  the  triple  gears  will 
come  in  the  same  plane  with  their  mates,  and  that  the  countershaft 
E  will  be  in  line  for  the  engagement  of  the  slip  pinion  K  with  either 
gears  M  or  N. 

Figure  185  gives  a  front  elevation  and  Fig.  186  a  rear  elevation 
of  the  Flather  quick  change  gear  device,  which  is  a  simple  and 


212 


MODERN   LATHE  PRACTICE 


practical  device  and  apparently  well  adapted  for  the  purpose,  as 
most  of  their  devices  are  and  have  been  for  many  years. 

From  here  the  motion  is  transmitted  by  a  train  of  gears,  which 
will  be  described  later,  to  the  gear  D,  which  drives  shaft  A  in  the 
feed  box.  This  shaft  is  cut  for  a  part  of  its  length  with  teeth  to 
form  a  long  pinion,  and  on  this  portion  slides  the  lever  E.  The 
shaft  B  carries  the  cone  of  gears  usual  in  arrangements  of  this 
kind,  and  pivoted  in  the  lever  E,  but  not  shown  in  any  of  these  cuts, 
is  the  usual  intermediate  gear,  which  meshes  with  the  teeth  cut  in 
the  shaft  A,  and  can  be  brought  into  mesh  with  any  of  the  series 
of  gears  on  the  shaft  B. 


FIG.  186.  —  Rear  Elevation  of  Flather's  Quick  Change  Gear  Device. 

The  locking  pin  F  locates  the  lever  in  each  of  its  different  po- 
sitions by  entering  into  the  appropriate  hole  drilled  in  the  face  of  the 
gear  box.  G  is  a  steel  plate  fastened  to  the  lower  edge  of  the  box, 
and  provided  with  a  notch  to  match  each  locking  pin  hole.  A  pro- 
jection on  the  inside  of  the  lever  E  enters  one  of  these  notches,  and 
prevents  the  lever  from  being  shifted  along  the  shaft  until  the  inter- 
mediate gear  has  been  dropped  clear  of  the  gears  on  the  shaft  B. 

A  new  feature  in  this  device  is  the  fact  that  means  are  provided 
in  the  gear  box  for  giving  three  different  speeds  to  the  feed  rod  or 
lead  screw  for  each  position  of  lever  F.  The  shaft  C  has  turning 
loosely  upon  it  two  gears,  H  and  J,  whose  hubs  are  cut  to  the  form 


RAPID  CHANGE  GEAR  MECHANISMS  213 

of  clutch  teeth.  Between  these  two  gears  is  a  third  one  marked  I, 
which  has  clutch  teeth  at  both  ends  of  its  hub,  and  is  splined  to  the 
shaft,  but  free  to  move  endwise.  An  endwise  movement  is  given 
to  it  through  the  lever  K;  which  projects  through  the  top  of  the 
box. 

When  in  the  position  shown,  the  motion  is  evidently  trans- 
mitted from  shaft  B  to  shaft  C  through  the  gear  I,  and  its  mating 
gear  in  the  series  on  the  shaft  B.  The  gear  I  may  be  thrown  either 
to  the  right  or  left,  and  thus  be  disengaged  from  its  mate,  but  con- 
nected by  the  clutch  teeth  on  its  hub  with  either  of  the  gears  H  or  J. 
As  these  are  run  by  their  corresponding  drivers  at  different  rates  of 
speed,  each  position  of  the  lever  E,  by  shifting  lever  K,  will  give 
three  different  speeds,  or  twenty-seven  in  all.  This  is  the  usual 
way  of  changing  the  turning  feeds  in  the  shop  of  the  manufacturer; 
the  lever  E  being  located  at  a  suitable  station,  the  roughing  and 
finishing  feeds  are  obtained  by  the  lever  K. 

The  gear  I  has  a  spring  pin  in  its  hub  which  engages  suitable 
depressions  in  shaft  C,  and  thus  prevents  the  lever  K  from  being 
jarred  out  of  position.  The  shaft  C  is  extended  through  the  gear 
box  and  carries  a  pinion  and  clutch  L,  which  may  be  moved  to  the 
right  to  engage  the  clutch  on  the  lead  screw,  or  moved  to  the  left 
to  mesh  with  the  gear  on  the  feed-shaft. 

The  27  feeds  and  threads  mentioned  are  further  increased  to 
54  by  means  of  a  sliding  gear  which  meshes  with  the  wide-faced 
gear  D  and  is  moved  in  or  out  by  the  projecting  hub  seen  at  M. 
Suitable  gearing  in  the  case  N  alters  the  ratio  of  rotation  for  these 
two  positions.  While  this  arrangement  gives  54  feeds  varying 
from  7  to  448  per  inch,  the  threads  from  2  to  128,  the  range  is  still 
further  extended  to  permit  the  cutting  of  odd  threads,  metric 
pitches,  etc.,  since  the  gear  D  may  be  removed  and  one  of  any 
suitable  number  of  teeth  inserted  in  its  place. 


CHAPTER  XI 

LATHE  TOOLS,  HIGH-SPEED  STEEL,  SPEEDS  AND  FEEDS,   POWER  FOR 
CUTTING-TOOLS,  ETC. 

Lathe  tools  in  general.  A  set  of  regular  tools.  Tool  angles.  Materials  and 
their  characteristics.  Their  relation  to  the  proper  form  of  tools.  Be- 
havior of  metals  when  being  machined.  The  four  requisites  for  a  tool. 
The  strength  of  the  tool.  The  form  of  the  tool.  Degree  of  angles. 
Roughing  and  finishing  tools.  Spring  tools.  Tool-holders.  Grinding 
tools  for  tool-holders.  Dimensions  of  tools  for  tool-holders.  The  Arm- 
strong tool-holders.  Economy  of  the  use  of  tool-holders.  High-speed 
steel.  A  practical  machinist's  views  on  high-speed  steel  tools.  Condi- 
tions of  its  use.  Preparing  the  tool.  Testing  the  tool.  Speeds  and 
feeds.  Much  difference  of  opinion.  Grinding  the  tools.  Amount  of 
work  accomplished  by  high-speed  steel  tools.  Average  speed  for  lathes 
of  different  swing.  Speeds  of  high-speed  steel  drills.  Mr.  Walter 
Brown's  observations  on  high-speed  steel.  Its  brittleness.  Its  treat- 
ment. The  secret  of  its  successful  treatment.  Method  of  hardening 
and  tempering.  Method  of  packing.  Making  successful  taps.  Speeds 
for  the  use  of  high-speed  steel  tools.  Economy  in  the  use  of  high- 
speed steel  tools.  Old  speeds  for  carbon  steel  tools.  Modern  speeds. 
Relative  speeds  and  feeds.  Modern  feeds  for  different  materials. 
Lubrication  of  tools.  The  kind  of  lubricant.  Applying  the  lubri- 
cant. Lubricating  oils.  Soapy  mixtures.  Formula  for  lubricating 
compound.  Improper  lubricants.  Various  methods  of  applying  lubri- 
cants. The  gravity  feed.  Tank  for  lubricant.  Pump  for  lubricant. 
Power  for  driving  machine  tools.  Calculating  the  power  of  a  driving- 
belt.  Impracticability  of  constructing  power  tables.  Collecting  data 
relating  to  these  subjects.  Flather's  "  Dynamometers  and  the  Trans- 
mission of  Power."  Pressure  on  the  tool.  Method  of  calculating  it. 
Flather's  formula.  Manchester  Technology  data.  Pressure  on  tools. 

WITH  comparatively  slight  exceptions  the  ordinary  lathe  tools 
are  of  the  same  form  as  those  used  in  the  time  of  the  old  chain  lathe 
with  a  wooden  bed.  While  the  modern  machinist  has  found  some 
new  shapes  for  special  work  and  has  been  provided  with  all  sorts 
and  forms  of  tool-holders,  and  it  is  probable  that  many  new  and 

214 


LATHE  TOOLS,   HIGH-SPEED   STEEL,   ETC. 


215 


perhaps  improved  forms  will  be  brought  out  in  the  future,  the 
same  old  forms  will  probably  be  used  for  a  considerable  part  of 
lathe  work  as  long  as  there  is  a  lathe  to  use  them  on. 


u 


u 


u 


/L    t\ 


10 


A 


12 


13 


FIG.  187.  —  A  Set  of  Ordinary  Lathe  Tools. 

A  set  of  fourteen  of  these  time-honored  tools  is  shown  in  Fig. 
187,  which  are  usually  known  by  the  following  names,  the  numbers 
given  in  the  engraving  being  referred  to : 


1.  Right-hand  Side  Tool. 

2.  Left-hand  Side  Tool. 

3.  Right  Bent  Side  Tool. 

4.  Right-hand  Diamond  Point. 

5.  Left-hand  Diamond  Point. 

6.  Round  Nose  Tool. 

7.  Cutting-down  Tool. 


8.  Cutting-off  Tool. 

9.  Narrow  Round  Nose  Tool. 

10.  Wide  Round  Nose  Tool. 

11.  Inside  Boring  Tool. 

12.  Straight  Thread  Tool. 

13.  Bent  Thread  Tool. 

14.  Inside  Thread  Tool. 


216  MODERN  LATHE  PRACTICE 

In  nearly  all  these  tools  their  names  indicate  their  .uses,  which 
is  quite  apparent  also  from  their  form. 

The  question  of  the  proper  angles  to  which  lathe  tools  should  be 
formed  is  an  important  one  and  there  are  a  good  many  theories  in 
relation  to  the  subject.  It  is  a  matter  of  continual  discussion 
among  shop-men  who  are  inclined  to  disagree  very  much  on  the 
subject.  It  is  altogether  probable  that  this  disagreement  is  not  so 
much  that  the  question  is  one  impossible  of  solution  as  it  is  that 
each  man  determines  the  question  for  himself  from  the  standpoint 
of  his  own  experience  and  with  the  range  of  material  with  which 
he  has  to  work:  otherwise,  with  the  conditions  which  govern  the 
work  under  his  observation. 

These  conditions  are  so  varied  and  so  numerous  that  no  fixed 
rules  for  forming  tools  to  meet  them  all  is  possible.  Some  of  them 
are  these: 

We  have  ordinarily  to  handle  such  materials  as  tool  steel, 
machine  steel,  steel  castings,  wrought  iron,  cast  iron,  bronze,  brass, 
copper,  aluminum,  babbitt  metal,  hard  rubber,  vulcanized  fiber, 
rawhide,  and  a  number  of  others  constantly  coming  to  hand.  These 
substances  as  here  mentioned  give  a  very  wide  range  to  the  kind 
and  shape  of  the  tools  that  it  will  be  proper  to  use.  But  there  are 
varying  degrees  and  conditions  in  the  same  material  that  still 
further  complicate  the  question. 

Steel  may  be  hard  and  brittle,  or  it  may  be  soft  and  tough.  It 
may  be  of  any  percentage  of  carbon  up  to  and  perhaps  over  one 
hundred  points,  and  still  we  must  make  a  tool  to  cut  it. 

Wrought  iron  may  have  somewhat  similar  properties  as  steel, 
but,  of  course,  in  a  much  less  degree. 

The  alloys  of  copper  commonly  known  as  hard  bronze,  nickel 
bronze,  gun  metal,  brass,  yellow  brass,  and  so  on,  through  an 
almost  endless  variety  of  mixtures,  will  require  almost  as  many 
different  forms  as  must  be  used  in  turning  the  different  grades  of 
steel. 

And  so  it  is  to  a  greater  or  less  extent  with  all  the  different 
materials  with  which  we  have  to  deal. 

In  a  general  way  we  may  say  that  the  quality  of  the  material 
we  have  to  cut  will  influence  the  results  in  two  ways :  first,  as  to 
whether  it  is  hard  or  soft,  and  second,  whether  it  is  crystalline  or 


LATHE  TOOLS,   HIGH-SPEED   STEEL,   ETC.  217 

fibrous.  Its  varying  degrees  of  hardness  or  softness  determine 
whether  much  or  little  can  be  removed  in  a  given  time;  or,  what 
amounts  to  the  same  thing,  whether  the  speed  of  the  cutting  shall 
be  fast  or  slow,  and  whether  the  feed  shall  be  coarse  or  fine.  Its 
crystalline  or  its  fibrous  nature  will  make  considerable  difference 
in  the  top  angles  of  the  tools,  and  this  will  be  readily  seen  in  the 
tendency  of  the  crystalline  metal  to  break  up  into  small  chips,  while 
the  fibrous  turnings  will  curl  off  into  spiral  or  helical  shavings. 
Therefore  the  fibrous  material  will  have  the  sharper  angle  than  that 
designed  for  the  crystalline  structure  of  metal. 

Of  course  all  tools  must  be  harder  than  the  material  they  are  to 
cut;  at  the  same  time  they  must  not  be  so  hard  as  to  be  brittle,  or 
be  made  of  a  quality  of  steel  that  becomes  brittle  when  hardened, 
but  tough  and  strong  and  capable  of  maintaining  their  cutting- 
edge  uninjured  during  their  ordinary  use.  The  fact  that  they  do 
this  will  be  best  evidence  of  the  correctness  of  their  angles,  provided 
they  have  done  the  proper  amount  of  work,  that  is,  have  been  run 
under  satisfactory  conditions  of  speed  and  feed. 

In  the  proper  design  of  a  tool,  with  angles  to  suit  the  work,  there 
are  four  points  to  be  remembered,  namely:  cutting  capacity,  that 
is,  as  the  machinist  would  say,  to  "dig  in";  the  right  angle  of  relief 
or  clearance;  proper  strength;  and  durability  or  lasting  quality  of 
edge  and  point. 

That  these  are  not  simply  distinctions  without  a  difference  is 
seen  if  we  analyze  the  question  a  moment.  Cutting  capacity  is  the 
tendency  to  dig  into  the  work,  to  bury  itself  in  the  metal.  This 
is  directly  opposed  by  the  greater  or  less  angle  of  clearance  or  relief. 
The  tendency  to  bury  itself  in  the  work  is  due  to  the  "rake  "  and  the 
top  angle,  but  principally  to  the  rake  in  a  slide  tool  and  the  top 
angle  in  a  cutting-down  tool. 

These  points  will  be  clear  upon  reference  to  the  engraving,  in 
which  Fig.  188  show  the  angles  for  a  slide  tool,  and  Fig.  189  those 
for  a  cutting-down  tool. 

As  to  the  proper  strength.  The  tool  will  be  much  stronger  with 
more  obtuse  angles,  yet  more  obtuse  angles  will  be  to  the  injury 
of  its  other  qualities.  Again,  if  the  point  or  the  edge  is  too  keen, 
that  is,  at  too  acute  an  angle,  its  strength  and  durability  are  both 
jeopardized. 


218 


MODERN   LATHE   PRACTICE 


r-f 


FIG.  188.  —  The  Proper  Angles  for  a 
Side  Tool. 


Hence  we  are  forced  to  the  conclusion  that  the  form  of  the  tool 
is  not  only  largely  governed  by  the  kind  and  quality  of  the  material 
to  be  acted  upon,  but  is  in  itself,  by  reason  of  the  conditions  of  its 
construction  and  use,  very  largely  a  question  of  compromises  on  the 
one  side  or  the  other,  and  frequently  on  both. 

Referring  again  to  Fig. 
188  showing  a  side  tool,  and 
Fig.  189  showing  a  cutting- 
down  tool,  both  of  which 
are  types  of  nearly  all  the 
various  forms,  attention  is 
called  to  the  various  angles 
and  their  designations,  which 
will  apply  equally  well  to 
all  cutting-tools. 

It  will  be  seen  that  the  clearance  angle  may  be  anywhere  be- 
tween a  vertical  line  and  10  degrees  from  it.  The  face  angle  may 
have  a  like  variation  although  we  frequently  see  tools  having  an 
angle  as  great  as  25  degrees.  The  "rake"  or  top  cutting  angle  will 
be  any  angle  from  horizontal  to  25  degrees,  seldom  more. 

In  a  general  way  it  may  be  said  that  in  cutting  steel  the  softer 
the  material  the  more  acute  may  be  the  angles,  and  that  for  very 
hard  steel  the  angles  must  be  very  obtuse. 

For  cutting  wrought  iron  the  tool  with  angles  too  acute  is  liable 
to  bury  itself  in  the  work  and  break,  on  account  of  the  fibrous 
nature  of  the  material. 

Again,  in  tools  for  brass 
work  the  angles  will  be 
very  slight,  otherwise  the 
tool  will  plunge  into  the 
work  and  spoil  it.  It  is  a 
common  saying  in  the  shop, 
when  the  relative  angles  of 


FIG.  189.  —  The  Proper  Angles  for  a 
Cutting-down  Tool. 


tools  for  steel  and  brass  are  discussed,  "  Whatever  you  do  for  a 
steel  tool,  do  the  opposite  for  a  brass  tool."  (The  metals  mentioned 
being  those  to  be  machined,  of  course.)  And  this  is  literally  true 
as  far  as  angles  are  concerned. 

In  the  general  working  of  steel  and  cast  iron  in  many  shops  where 


LATHE  TOOLS,   HIGH-SPEED  STEEL,   ETC.  219 

the  workmen  get  their  tools  from  the  tool-room  ready  ground,  the 
tool  angles  are  the  same  for  both  metals  and  of  all  degrees  of  hard- 
ness, unless  the  foreman  has  special  work  to  do  requiring  a  special 
form  of  tool.  Another  set  of  tool  angles  are  used  for  brass  and 
bronze. 

When  bronze  is  very  tough  as  well  as  hard,  a  special  form  of 
tool  will  be  required,  and  this  will  sometimes  very  nearly  approach 
the  form  of  a  tool  for  turning  steel,  including  considerable  rake  and 
top  angle.  Often  a  diamond-point  tool  is  used.  (See  Nos.  4  and  5 
in  Fig.  187.) 

Tools  are  of  two  general  classes  according  to  their  use,  that  is, 
for  roughing  and  for  finishing.  The  former  must  be  made  mostly 
for  strength  and  are  intended  for  deep  cuts,  coarse  feeds,  and  slower 
rates  of  speed;  while  the  finishing  tools  are  for  high  speeds,  fine 
feeds,  and  shallow  cuts.  Fine  feeds  are  not,  however,  always  used, 
as  it  is  a  common  condition  to  use  very  light,  scraping  cuts,  with  a 
broad  tool  and  a  coarse  feed.  This  is  notably  the  case  in  finishing 
the  inside  of  engine  cylinders.  The  author  has  seen  such  a  cut  of 
nearly  an  inch  feed,  the  tool  being  very  carefully  ground  and  acting 
more  as  a  scraper  than  a  cutting-tool.  In  this  case  the  angles  of 
the  tool  were  very  slight. 

On  outside  work,  that  is,  turning  rather  than  boring,  a  finishing 
tool  with  a  broad  cutting  edge  is  frequently  made  of  an  inverted 
U-shaped  form  and  called  a 
" spring  tool,"  or  a  "goose- 
neck," which  is  shown  in 
Fig.  190,  the  cutting-edge 
A  being  nearly  straight 


across,  or  parallel  with  the  FIG.  190. -A  Spring  Tool  or  "Gooseneck." 
surface  of  the  work.  When  there  seems  to  be  too  much  " spring" 
in  the  action  of  the  tool,  a  small  block  of  wood  is  inserted  at  B,  to 
furnish  some  support  for  the  cutting  edge  and  prevent  chattering. 

This  form  of  tool  is  not  nearly  as  much  used  as  formerly.  In 
fact  the  later  development  of  turning  tools  has  been  toward  more 
simple  forms,  which,  under  modern  conditions,  seem  better  adapted 
to  the  general  line  of  work. 

While  there  are  still  very  many  of  the  ordinary  lathe  tools  such 
as  has  just  been  described,  that  are  in  e very-day  use  in  nearly  all 


220 


MODERN   LATHE  PRACTICE 


shops,  the  use  of  tool-holders,  designed  for  holding  tools  made 
from  small  square  or  round  rods  of  tool  steel,  has  very  much 
increased. 

This  innovation  was  started  before  the  advent  of  the  now  well- 
known  " self-hardening,"  or  " high-speed"  tool  steels,  that  have  so 
changed  machine  shop  conditions  and  which  followed  the  intro- 
duction of  "Mushet"  steel  a  number  of  years  ago. 

These  tool-holders  have  been  made  in  great  variety  and  pro- 
fusion and  much  ingenuity  has  been  displayed  in  producing  what 
each  maker  thinks  is  at  once  the  most  convenient,  the  strongest, 
and  the  best. 

Some  of  these  holders  use  tools  made  by  simply  grinding  a  slight 
notch  in  the  bar  and  breaking  off  pieces  of  the  proper  lengths, 
whose  ends  are  ground -to  the  desired  form,  while  others  require  a 
special  form  of  cutting-tool  that  is  usually  drop  forged,  fitted,  and 
tempered.  It  is  fair  to  assume  that  on  general  principles  and  for 
general  use  the  tools  made  from  a  bar  will  be  the  most  useful,  since 


o 


A 


FIG.  191.  —  A  Set  of  Ten  Tools  for  a  Tool-Holder. 

it  is  always  the  most  convenient.  The  machinist  having  a  bar  of  tool 
steel  of  the  proper  size  may  produce  tools  of  any  form,  and  to  fit  any 
of  his  different  tool-holders,  according  to  which  is  best  suited  to 
his  particular  work. 

The  matter  of  grinding  these  tools  is  a  very  simple  one.  The 
regular  shapes,  and  about  all  the  shapes  that  will  be  needed,  are 
shown  in  the  engraving,  Fig.  191,  in  which  the  angle  is  specified. 
Thread  tools  may,  of  course,  be  added  to  the  list,  and  so  also  may 
some  forms  of  inside  boring  and  threading  tools. 

The  dimensions  of  the  steel  used  for  these  tools  for  light  lathe 
work  is  T3B  inch  and  J  inch  square.  For  medium  lathe  work,  T56-,  f, 
T76,  and  J  inch  square.  For  heavy  lathe  work,  f ,  f ,  f ,  1,  1J'  inch 
square. 

There  are  many  different  brands  and  grades  of  so-called  high- 


LATHE  TOOLS,   HIGH-SPEED  STEEL,   ETC. 


221 


speed  or  self -hardening  steel.  As  between  the  leading  brands  there 
is  very  little  difference  in  efficiency;  some  excelling  slightly  in  one 
respect,  or  upon  one  class  of  materials  to  be  machined,  while 
another  brand  seems  to  work  better  on  another. 

As  to  the  best  form  of  tool-holder,  there  will,  of  course,  be 
honest  differences  of  opinion,  and  each  machinist  will  have  his 
favorite  forms. 

Probably  there  are  more  Armstrong  tool-holders  used  than  any 
other,  and  in  Fig.  192  is  given  views  of  their  usual  forms.  Their 
uses  are  plainly  indicted  by  their  names  and  forms. 


STRAIGHT  CUT  OFF  TOOL 


BORING  TOOL 

FIG.  192.  —  A  Set  of  Armstrong  Tool-Holders. 

In  Fig.  193  is  shown  at  A  a  good  form  of  tool-holder  for  regular 
straight  work.  At  B  is  shown  a  tool-holder  and  tool  for  cutting 
threads.  It  will  be  seen  that  as  this  tool  is  of  parallel  form  through- 
out its  length,  it  is  only  necessary  to  grind  off  the  top  as  it  becomes 
dulled,  and  raise  it  to  the  proper  position  to  compensate  for  the 
amount  ground  away,  in  order  to  always  have  a  fresh  surface  and 
of  proper  cutting  form  and  angle. 

The  economy  of  the  use  of  tool-holders  should  be  apparent  to 
any  one  who  studies  the  conditions  even  superficially. 

The  one  fact  that  by  their  use  the  time  and  expense  of  the  forging 


222 


MODERN   LATHE  PRACTICE 


and  re-forging  of  tools  is  reduced  to  a  minimum,  and  in  fact  may  be 
almost  eliminated,  the  tools  to  be  so  treated  consisting  only  of  a 
very  few  special  tools  for  special  jobs  that  cannot  be  conveniently 
reached  by  such  tools  as  may  be  used  in  the  tool-holders,  is  amply 
sufficient  to  warrant  their  use  in  every  shop. 


FIG.  193.  —  The  Champion  Tool-Holder. 

The  facility  with  which  tools  of  different  shapes  that  may  be  re- 
quired can  be  produced  is  also  an  important  reason  for  their  use. 

Another  reason  is  that  when  the  shop  is  once  equipped  with 
tool-holders,  the  cost  for  the  steel  for  making  the  tools  is  very  slight 
as  compared  with  the  heavy  forged  tools  formerly  used. 

The  modern  demand  for  high-speed  steel  for  lathe  tools  and 
its  high  price  makes  it  necessary,  from  reasons  of  economy,  to  use 
small  tools;  hence  tool-holders. 


FIG.  194.  —  The  "Three-in-one"  Tool-Holder. 

In  reference  to  the  use  of  high-speed  steel  in  a  very  large  and 
general  way,  for  all  classes  of  work  upon  which  it  is  possible  to  use 
it,  there  seems  to  be  no  doubt.  It  has  been  proven  many  times,  in 
many  places,  under  many  conditions  and  on  almost  every  con- 
ceivable material  that  has  to  be  handled  in  machine  tools,  that  it 
has  "come  to  stay"  and  that  any  information  regarding  it  is  of 
practical  use. 

The  following  remarks,  giving  the  experience  of  one  practical 


LATHE  TOOLS,   HIGH-SPEED   STEEL,   ETC.  223 

and  observing  machinist  whose  name,  unfortunately,  is  not  at  hand 
so  that  proper  credit  can  be  given  him,  are  here  introduced  as  being 
valuable  in  this  connection,  and  practical  from  the  machine  shop 
point  of  view: 

"The  first  thing  is  to  make  up  one's  mind  as  to  the  quality  or 
kind  of  steel  to  use,  which  means  to  be  satisfied  with  the  steel  which 
has  been  found  to  work  best  in  one's  own  shop.  This  has  been  a 
difficult  matter  for  superintendents  and  foremen  to  decide,  because 
it  is  so  hard  to  discover  the  best  way  to  determine  which  steel  will 
do  the  most  work,  and  experience  has  taught  most  of  us  that  any 
of  our  high-speed  steels,  when  properly  treated,  will  do  considerably 
more  work  than  the  machine  is  capable  of. 

"I  do  not  think  it  advisable  to  have  too  many  different  kinds  of 
stock  in  the  works ;  results  depend  entirely  upon  the  way  of  forging 
and  treating  the  tool.  If  the  tool-maker  is  familiar  with  one  or 
two  grades  of  the  best  high-speed  steel,  and  the  quality  is  found 
satisfactory,  and  bringing  about  the  best  results  that  the  machines 
can  stand  up  to,  these  are  the  steels  that  should  be  adopted. 

"Each  of  these  steels  must  be  treated  differently,  and  if  the  tool- 
maker  succeeds  in  treating  one  grade  properly  and  understanding 
it  thoroughly,  it  means  much  time  saved  and  better  results  in  the 
shop. 

"  In  introducing  the  use  of  high-speed  steel  in  a  shop,  like  every- 
thing else  that  is  to  be  a  success,  one  must  start  right.  That  is,  the 
work  should  be  undertaken  by  some  responsible  person  —  superin- 
tendent, foreman  or  speed  boss,  in  other  words,  the  man  who  is 
responsible  for  the  work  turned  out  in  the  machine  shop.  All  tools, 
of  course,  have  some  particular  way  of  treating,  which  should  be 
understood  by  the  person  in  charge.  Now  it  is  'up  to  the  forger/ 

"The  person  in  charge  should  see  that  the  tool  has  its  proper 
treatment,  as  success  in  most  cases  lies  with  the  treatment.  When 
the  tool  is  finished,  and  the  superintendent  or  foreman  is  satisfied 
that  it  has  been  properly  treated  in  accordance  with  directions,  it 
is  ready  for  grinding  and  for  making  a  test.  It  should  be  ground  on 
a  wet  emery  wheel,  and  care  taken  to  heat  the  tool  just  so  it  can 
be  touched  with  the  fingers. 

"The  tool  once  ground  and  ready  to  do  the  work,  the  question 
often  arises,  'What  lathe,  planer,  or  machine  are  we  going  to  put 


224  MODERN  LATHE   PRACTICE 

it  into? '  In  most  cases  when  a  new  tool  is  tried,  it  is  put  in  a  lathe, 
to  do  turning;  so  naturally  the  superintendent  or  foreman  would 
pick  out  the  best  lathe  that  was  in  the  shop,  i.  e.,  the  lathe  that  was 
considered  to  have  the  most  power. 

"Being  now  ready  to  make  the  test,  it  is  generally  tried  on  steel; 
that  is  considered  by  most  superintendents  and  foremen  the  sever- 
est test  to  make.  Take  a  piece  of  steel  of  almost  any  diameter, 
and  of  the  quality  most  used  in  the  shop,  and  prepare  to  take  the 
cut.  It  seems  to  puzzle  most  every  foreman  to  know  just  what  to 
do  and  where  to  start.  I  speak  now  of  what  I  have  seen,  and  of 
the  men  who  are  sometimes  sent  by  the  steel  makers  to  demon- 
strate the  use  of  their  steels. 

•  "I  think  the  proper  way  is  to  get  at  least  one  dozen  shafts  of 
a  standard  size  that  are  used  in  the  regular  line  of  product,  and  to 
first  look  up  the  exact  time  it  took  to  finish  or  rough  off  the  previ- 
ous lot;  then  to  determine  about  what  percentage  of  time  would 
be  considered  a  fair  gain  to  warrant  adopting  the  steel,  based  on 
the  price  per  pound  of  the  steel  being  used.  Let  it  be  based  at 
25  per  cent,  which  I  find  in  most  shops  can  be  accomplished,  and 
the  lathe  be  speeded  up  faster  than  when  the  last  lot  was  turned, 
starting  with  the  same  feed  and  about  the  same  cut,  which  most  any 
lathe  will  stand.  The  superintendent  finds,  after  he  has  roughed 
off  about  two  or  three  pieces,  that  the  tool  seems  to  stand  up  all 
right. 

"The  next  step  is  to  find  out  about  the  speeds  and  feeds.  The 
first  thing  is  to  increase  the  feed  with  the  same  speed  the  machine 
is  running  at.  In  most  cases  which  I  have  seen,  after  the  tool  has 
traveled  a  certain  distance  the  cutting  edge  would  break  or  crumble, 
and  the  foreman  would  say,  '  Just  as  I  expected.  All  this  high- 
speed steel  will  do  the  same  thing!'  forgetting  he  had  just  been 
doing  over  25  per  cent  more  work  than  ever  before,  without  the 
least  bit  of  trouble. 

"Now  the  tool  is  taken  out  and  looked  over,  and  it  is  found  that 
a  portion  of  its  cutting  edge  has  been  broken  off.  Here  is  where 
most  foremen  make  a  mistake;  they  take  the  tool  back  to  the 
forger  or  tool  dresser  to  have  it  re-dressed  and  treated  over.  If 
it  is  only  broken  off  slightly  and  can  be  ground,  even  if  it  take  ten 
or  fifteen  minutes  to  grind,  it  should  be  done  by  all  means.  My 


LATHE  TOOLS,   HIGH-SPEED  STEEL,   ETC.  225 

experience  has  taught  me  it  will  prove  a  better  tool  than  before, 
but  care  must  be  taken  not  to  overheat  in  grinding. 

"The  tool  is  now  put  back  in  the  lathe,  which  is  started  again; 
and  generally,  to  one's  astonishment,  it  will  be  found  that  the  tool 
will  stand  up  all  right.  One  should  not  be  too  anxious  to  break 
the  tool  again  (!),  but  should  turn  up  two  or  three  more  pieces  with 
an  increase  of  feed,  keeping  a  record  of  the  time  it  takes  to  turn  up 
each  piece. 

"Once  convinced  that  the  tool  will  stay  up  all  right  with  the 
increase  of  feed,  the  foreman  can  increase  the  speed  one  step  on  the 
cone.  About  the  time  this  is  done,  it  is  found  either  that  the  belt 
slips,  the  lathe  is  stalled,  or  the  countershaft  will  not  drive.  (It  is 
my  opinion  that  in  most  all  machines  which  have  been  built  up  to  a 
year  or  so  ago  the  countershafts  are  not  strong  enough  in  com- 
parison with  the  machine  tools.)  Now,  no  doubt  if  these  things  had 
not  occurred  the  tool  would  have  done  better;  but  in  this  case, 
reduce  the  speed,  and  finish  the  twelve  shafts,  which  it  will  probably 
be  found  can  be  done  without  grinding  the  tool. 

"When  the  shafts  are  all  roughed  off  and  finished,  the  foreman 
will  find  to  his  great  astonishment  that  by  actual  time  the  lathe 
has  produced  over  25  to  40  per  cent  more  work  than  ever  before. 
I  allude  to  the  lathe  using  most  all  ordinary  tool  steels. 

"At  this  point  it  is  up  to  the  superintendent  to  see  just  where  he 
is  at,  and  he  finds  in  looking  around  his  shop  that  there  is  hardly  a 
machine  that  he  can't  speed  up,  but  he  also  finds  that  the  speeds 
on  the  countershafts  are  all  too  slow.  This  means  that  he  has 
either  got  to  increase  his  speed  by  increasing  the  main  line,  or  buy 
new  pulleys  to  increase  his  countershafts. 

"In  most  instances  it  is  advisable  to  increase  the  speed  of  the 
countershaft,  but  by  doing  this  he  generally  finds  that  the  counter- 
shaft will  not  stand  the  speed.  If  the  machines  are  not  too  badly 
worn  out,  and  he  is  satisfied  that  he  can  get  at  least  25  per  cent  more 
work  out  of  the  tool  by  increasing  the  counter  speed,  by  all  means 
let  him  get  a  new  countershaft  and  treat  each  machine  this  way. 

"No  doubt  the  reader  will  know  the  results  that  some  of  us  have 
arrived  at  in  the  last  two  years.  In  regard  to  cutting  speeds  and 
feeds  there  has  been  and  always  will  be  difference  of  opinion,  and  it 
is  almost  impossible  to  determine  the  right  feeds  and  speeds,  whether 


226  MODERN   LATHE  PRACTICE 

it  is  for  steel  or  cast  iron,  and  for  the  operations  of  turning,  planing, 
or  milling;  the  work  varies  so  in  different  shops,  that  is/regarding 
the  construction  of  different  pieces,  the  amount  of  metal  there  is  to 
remove  from  each  piece,  and  how  accurately  the  work  has  to  be 
done. 

"  There  is  no  doubt  in  my  mind  that  the  makers  of  high-speed 
steel  have  awakened  the  management  of  different  shops,  and  it  is 
surprising  the  amount  of  work  which  can  be  accomplished  even 
with  the  old  machines,  with  very  little  redesigning.  There  is  no 
question  but  that  the  machine  shops  which  do  very  heavy  work 
have  not  the  necessary  power  for  the  use  of  high-speed  steels,  as  the 
power  should  be  used  if  the  machines  are  old  ones. 

"  Referring  again  to  the  question  of  grinding,  I  wish  to  state  that 
this  is  a  very  important  factor  in  the  use  of  high-speed  steels.  I 
have  seen  much  damage  done  to  the  tools,  in  many  instances  mak- 
ing it  necessary  to  treat  them  over,  and,  as  we  all  know,  this  takes 
much  time.  My  recommendation  for  grinding  is  to  let  one  man 
grind  all  the  tools,  and  be  responsible  for  them.  When  a  lathe 
hand  or  a  machine  hand  wants  his  tool  ground,  he  simply  gives  it  to 
the  man  who  is  responsible,  and  gets  another  the  same  size  and 
shape,  these  being  always  kept  ground  and  ready  for  service.  In 
this  way  the  tools  are  kept  uniform  and  ground  alike. 

"In  reference  to  the  amount  of  work  that  can  be  accomplished 
on  different  machine  tools,  the  writer  finds  that  the  feeds  have  been 
altogether  too  fine  on  most  makes  of  machines  up  to  the  time  that 
they  were  redesigned  for  high-speed  work.  Now  it  has  been 
demonstrated  that  high-speed  steel  has  come  to  stay,  and  we  all 
know  that  it  works  better  on  roughing  work  than  it  does  on  finish- 
ing. If  most  of  the  product  of  the  machine  department  is  to  be 
turned,  it  has  come  to  the  point  where  the  majority  of  work  must 
be  ground;  and  this  is  the  only  way  to  get  good  and  accurate  work, 
especially  where  the  strains  of  the  cut  spring  the  work.  Moreover, 
as  it  is  not  necessary  to  straighten  the  work  to  any  great  extent,  it 
certainly  means  a  great  saving,  as  many  of  our  readers  know.  The 
writer  is  not  a  builder  of  grinders,  but  merely  speaks  of  the  saving 
it  has  been  on  his  own  work. 

"  Below  is  a  fair  average  of  the  speeds  that  most  any  good  make 
of  lathe,  planer,  drill  press  or  radial  ought  to  stand  when  using 


LATHE  TOOLS,   HIGH-SPEED  STEEL,   ETC.  227 

high-speed  steel.  Every  lathe  has  a  face-plate  about  the  diameter 
of  the  swing  or  very  near  that.  Take  the  peripheral  speed  of  same 
by  feet  per  minute;  the  use  of  a  Warner  cut-meter  will  give  you 
the  speeds  instantly.  This  is  one  of  the  handiest  little  tools  that 
can  be  obtained,  and  no  machine  shop  is  complete  without  it.  The 
speed  must  be  taken  with  the  belt  on  the  largest  step  of  the  cone, 
with  the  back  gears  in.  The  speed  of  the  following  sizes  of  lathes, 
taken  from  a  large  face-plate  with  the  slowest  speed,  I  find  to  work 
very  well,  and  considerable  saving  has  been  effected  even  on  old 
lathes.  Of  course  the  feeds  will  have  to  be  determined  by  the 
amount  of  power  available: 

"  14-inch  swing  lathe;  slowest  speed  with  back  gears  in,  100  feet. 

16-inch  swing  lathe;  slowest  speed  with  back  gears  in,  90  feet. 

18-inch  swing  lathe;  slowest  speed  with  back  gears  in,  85  feet. 

20-inch  swing  lathe;  slowest  speed  with  back  gears  in,  75  feet. 

24-inch  swing  lathe;  slowest  speed  with  back  gears  in,  65  feet. 

30-inch  swing  lathe  ;  slowest  speed  with  back  gears  in,  60  feet. 

36-inch  swing  lathe;  slowest  speed  with  back  gears  in,  50  feet. 

42-inch  swing  lathe;  slowest  speed  with  back  gears  in,  30  feet. 

"  Larger  lathes  in  proportion. 

"  High-speed  twist  drills,  drilling  cast  iron,  ought  to  drill  the 
following,  if  we  have  the  power  and  feeds  : 


diameter,  speed  500  r.p.m.,  3J  inches  deep  in  one  minute. 

|-inch  diameter,  speed  400  r.p.m.,  2f  inches  deep  in  one  minute. 

f-inch  diameter,  speed  335  r.p.m.,  2J  inches  deep  in  one  minute. 

f-inch  diameter,  speed  290  r.p.m.,  2|  inches  deep  in  one  minute. 
1  -inch  diameter,  speed  250  r.p.m.,  2J  inches  deep  in  one  minute. 
IJ-inch  diameter,  speed  220  r.p.m.,  2J  inches  deep  in  one  minute. 
IJ-mch  diameter,  speed  200  r.p.m.,  2  inches  deep  in  one  minute. 
If-inch  diameter,  speed  185  r.p.m.,  If  inches  deep  in  one  minute. 
IJ-inch  diameter,  speed  175  r.p.m.,  If  inches  deep  in  one  minute. 

"  Larger  ones  in  proportion. 

"These  speeds  are  all  based  on  a  peripheral  speed  of  65  feet  per 
minute.  High-speed  drills  have  done  somewhat  better  than  this, 
however,  but  taking  into  consideration  the  time  of  grinding,  I  find 
that  this  speed  is  a  good  average  during  a  day's  run." 


228  MODERN   LATHE   PRACTICE 

Continuing  the  discussion  of  high-speed  steel  it  may  not  be 
amiss  to  say  that  it  is  yet  in  its  infancy,  and  as  far  as  can  now  be 
judged  it  has  a  most  brilliant  future  before  it.  It  has  its  short- 
coming as  every  comparatively  new  product  has,  but  when  we  con- 
sider how  long  it  took  to  develop  "machinery  steel"  to  its  present 
condition,  we  must  admit  that  high-speed  steel  has  a  record  that 
its  friends  may  be  proud  of. 

One  of  its  good  friends,  Mr.  Walter  Brown,  has  given  us  in  the 
columns  of  " Machinery"  some  excellent  ideas  on  this  subject,  in 
which  he  has  taken  much  interest  and  of  which  he  has  made  many 
valuable  observations  and  suggestions.  Among  other  good  things 
be  says : 

"In  spite  of  its  shortcomings,  however,  it  is  very  evidently  the 
cutting-tool  material  of  the  future,  both  because  of  its  superior 
qualities,  all  things  considered,  and  of  the  likelihood  that  most 
of  its  present  failings  will  be  overcome  as  manufacturers  get  a  better 
knowledge  of  its  nature  and  behavior. 

"The  chief  difficulty  in  the  way  of  its  use  now  is  its  exceeding 
brittleness.  Many  a  user  has  become  discouraged  with  the  result 
of  a  few  experiments  and  has,  because  of  finding  that  it  lacked  the 
'toughness  of  other  steels,  discarded  its  use  entirely.  More  experience 
would,  if  intelligently  obtained,  have  demonstrated  without  ques- 
tion the  great  value  of  this  new  product  of  the  metallurgist's  skill. 

"The  question  of  brittleness  is  largely  a  question  of  treatment; 
and  intelligent  experience  will  very  largely  obviate  the  difficulty 
so  that  it  will  be  tough  enough  to  stand  up  under  any  proper  con- 
ditions of  work.  Every  tool-dresser  knows  how  to  handle  carbon 
tool  steels,  and  is  guided  by  his  knowledge  of  their  qualities  at 
different  temperatures  as  indicated  by  their  varying  colors.  When 
he  gets  a  high-speed  steel  he  naturally  treatsvit  much  as  he  would 
carbon  steel. 

"This  is  where  most  of  the  trouble  begins.  The  smith  must 
learn  an  entirely  different  set  of  color  values  and  methods  of  treat- 
ment. He  thinks  that  if  he  has  succeeded  in  getting  a  hardness 
greater  than  that  of  his  file,  he  has  done  his  job.  That,  however, 
has  nothing  to  do  with  the  fitness  of  the  tool.  I  have  known  cases 
(with  a  certain  make  of  steel)  where  the  tool  would  do  the  best 
work  while  still  soft  enough  to  take  a  good  Swiss  file. 


LATHE  TOOLS,   HIGH-SPEED  STEEL,   ETC.  229 

"In  other  steels  a  similar  degree  of  softness,  or  even  a  degree 
of  hardness  much  greater  than  that  of  ordinary  steel,  would  not 
work,  the  tool  ' gumming  up'  and  rapidly  burning  up.  The  whole 
secret  lies  in  getting  the  tool  to  such  a  heat,  in  the  process  of  hard- 
ening, that  the  constituent  molecules  are  mobile,  and  then  'draw- 
ing' it  to  the  right  point. 

"When  the  tool-maker  has  mastered  this  secret,  he  can  pro- 
duce a  tool  of  high-speed  steel  as  tough  as  any  of  carbon  steel. 
The  mastering  of  it  is  largely  a  matter  of  experience.  Our  own 
experiences  have  been  so  interesting  and  successful  that1  I  have 
thought  they  might  prove  of  help  to  others,  and  I  submit  them 
herewith. 

"The  tools  should  be  placed  in  a  pipe  or  box,  well  surrounded 
with  small  pieces  of  coke,  the  packing  case  then  being  sealed  up 
with  fire  clay.  Small  holes  must  be  left  for  the  escape  of  gases, 
otherwise  the  clay  will  blow  out.  The  heating  furnace  should 
have  been  previously  heated  to  a  white  heat.  The  packing  case 
is  left  in  the  heat  from  one  to  three  hours,  according  to  size.  When 
removed  from  the  furnace,  the  box  should  be  as  near  the  bath  of 
fish  oil  as  may  be,  so  that  there  will  be  no  unnecessary  delay  in 
bringing  from  the  gases  of  the  packing  case  to  the  bath. 

"Exposure  to  the  air  not  only  causes  scale,  and  therefore  varia- 
tion in  size,  but  tends  to  affect  the  precision  of  the  hardening 
process.  Observance  of  this  caution  will  prevent  a  variation  of 
more  than  a  thousandth  of  an  inch  in  tools  of  moderate  size.  Car- 
bon steel  usually  varies  several  thousandths  as  a  result  of  hardening. 

"The  method  of  packing  will  depend  somewhat  upon  the  shape 
of  the  tool.  It  is  important  to  pack  in  such  a  way  that  all  tools 
packed  in  one  case  be  so  placed  as  to  be  handled  very  quickly,  and 
at  once  plunged  into  the  bath,  to  prevent  scaling  by  reason  of  con- 
tact with  the  air,  as  explained  above.  In  case  of  milling  cutters 
and  key-seat  cutters,  a  good  way  is  to  suspend  them  all  from  a  rod, 
each  separated  from  its  neighbors  by  a  slight  space,  sufficient  to 
allow  a  free  circulation  of  oil  when  plunged.  Neglect  of  this  caution 
will  be  very  likely  to  cause  cracks,  from  the  unequal  contraction  of 
the  cutters,  the  outer  edges  only  being  brought  into  immediate 
contact  with  the  bath,  and  therefore  shrinking  more  rapidly  than 
the  interior  parts. 


230  MODERN  LATHE  PRACTICE 

"For  taps,  drills,  and  similar  shaped  tools,  this  hardening  leaves 
the  steel  too  brittle,  and  as  soon  as  the  tool  has  become  a  little  dull 
it  breaks  off.  To  avoid  this  the  tool  can  be  drawn  as  can  a  carbon- 
steel  tool.  But  here,  too,  a  new  set  of  color  scales  must  be  learned. 
The  blue  heat  of  carbon  steel  is  not  enough  of  the  high-speed  steel. 
The  heat  must  be  carried  on  until  the  metal  reaches  a  greenish 
tinge.  It  is  then  allowed  to  cool  in  a  dry  place  free  from  air  drafts. 

"It  is  now  much  tougher  and  softer  than  before.  In  case  it 
needs  still  further  softening,  it  can  be  done  by  reheating,  bringing 
it  to  a  faint  red,  dull  enough  to  be  perceptible  only  in  a  dark  place 
(an  empty  nail  keg  is  convenient  for  this  use)  and  then  cooled  as 
before.  We  have  made  taps  as  small  as  -^  inch  in  diameter  to  be 
used  in  an  automatic  nut  tapping  machine,  about  the  hardest  work 
to  which  a  tap  can  be  put,  with  gratifying  results. 

"In  the  test  three  taps  cut  92,000  nuts,  an  average  of  almost 
31,000  nuts  per  tap;  with  carbon  steel  taps  we  cut  6,000  nuts  per 
tap.  No  effort  was  made  to  speed  up  the  machine,  the  test  being 
one  of  durability  only.  The  carbon  steel  taps  cost  about  ten  cents, 
and  the  high-speed  taps  about  forty,  or  four  times  as  much. 
The  latter,  however,  cut  about  five  times  as  many  nuts.  Besides 
this,  there  is  also  to  be  taken  into  account  the  more  important 
saving  in  the  time  used  formerly  for  stopping  the  machine,  and  re- 
moving and  grinding  taps,  which  is  five  times  as  great  when  carbon 
steel  taps  are  used. 

"This  is  not  mentioned  as  a  particularly  demonstrative  test, 
but  merely  to  show  that  high-speed  steel  can  be  profitably  used 
for  small  tools,  if  properly  treated.  Another  place  where  we  are 
using  high-speed  steel  with  profit  and  satisfaction  in  small  tools  is 
in  drills.  The  saving  here  is  very  marked;  but  the  statements  and 
claims  of  several  makers  of  such  drills  is  not  verified  by  our  expe- 
rience. We  find  that  we  can  run  such  a  drill  at  about  double 
the  speed  of  the  ordinary  drill,  and  at  the  same  time  cut  more 
holes. 

"Makers  of  the  new  steels  are  in  the  habit  of  making  large  claims 
as  to  speeds  attainable.  We  have  tried  about  every  such  steel  on 
the  market,  giving  each  a  thorough  test.  Our  experience  usually 
bears  out  the  moderate  statements,  and  sometimes  the  extrava- 
gant ones,  put  forth  by  some  makers  as  to  what  is  possible.  For 


LATHE  TOOLS,   HIGH-SPEED   STEEL,   ETC. 

instance,  we  have  cut  a  y1^  chip,  -£%  feed,  at  a  rate  of  266  feet  per 
minute  peripheral  speed,  from  a  rod  of  machine  steel. 

"Such  speeds  are  possible  for  short  periods;  but  whoever  buys 
a  rapid  cutting  steel  with  the  expectation  of  maintaining  such  speed 
will  be  sadly  disappointed.  With  a  fine  feed,  even  four  hundred 
feet  per  minute  can  be  cut  under  very  favorable  circumstances. 
But  think  of  the  chip  that  comes  off!  In  case  of  steel  the  chip  is 
no  such  thing  as  we  are  accustomed  to,  breaking  into  short  pieces 
and  dropping  into  the  box  below. 

"At  a  speed  of,  say,  two  hundred  feet  per  minute,  the  chip 
comes  writhing  and  twisting,  almost  red  hot,  in  a  continuous  length, 
shooting  here  and  there,  everywhere  but  the  chip  box;  and  quick 
must  be  the  workman  that  manages  to  keep  well  out  of  the  way 
of  it,  for  it  'sticketh  like  a  brother'  when  once  he  gets  tangled  in  it. 

"  Possibly,  in  time,  a  way  will  be  found  to  take  care  of  such  chips. 
Until  this  is  done,  however,  a  moderate  speed  is  most  desirable.  We 
find  that  on  steel,  where  there  is  no  considerable  thickness  of  metal 
to  remove,  a  speed  of  one  hundred  feet  a  minute  is  very  satisfactory. 
This  allows  taking  care  of  chips,  and  the  tools  stand  up  well  under 
it.  In  turning  gray  iron,  where  the  scale  is  to  be  removed,  about 
seventy  feet  per  minute  is  giving  us  the  best  results.  Naturally, 
however,  there  being  so  many  different  kinds  of  materials  to  work 
up,  and  each  one  of  these  varying  more  or  less  themselves,  there  can 
be  no  set  rule  for  speed.  Each  job  will  work  out  a  rate  for  itself. 
The  main  thing  is  to  get  out  the  job  as  fast  and  as  well  as  possible, 
and  at  the  same  time  to  lose  as  little  time  as  may  be  in  grinding  the 
tool. 

"Another  word  about  the  saving  to  be  effected.  This  will 
depend  among  other  things  upon  the  number  of  machines  that  are 
run.  If  only  one  machine  runs  on  a  job,  there  will  not  be  a  saving 
of  two  thirds  simply  because  the  speed  is  trebled.  It  must  be 
remembered  that  perhaps  50  per  cent  of  the  time  for  doing  a  job 
on  a  single  machine  is  used  in  jigging  the  piece  and  setting  the  tool. 

"The  high  initial  cost  of  the  new  steels  has  made  it  necessary  to 
devise  means  for  reducing  the  quantity  of  metal  in  the  tools  used. 
The  result  has  been  the  production  of  some  very  ingenious  schemes 
for  holding  cutters.  The  lathe  tool  holder  is,  of  course,  familiar 
to  all.  Milling  cutters,  hollow  mills,  and  reamers  with  inserted 


232  MODERN  LATHE  PRACTICE 

teeth,  are  scarcely  less  familiar.  It  is  now  true  that  we  are  making 
all  these  tools  with  inserted  cutters  of  rapid  cutting  steel  at  less  cost 
than  the  old  carbon  steel  tools.  At  the  same  time  they  are  doing 
from  three  to  ten  times  the  work,  and  at  a  much  greater  speed." 

The  question  of  speeds  and  feeds  is  an  important  one  in  con- 
nection with  that  of  lathe  tools,  whether  the  old  carbon  steel  is 
used  or  the  new  high-speed  steel  known  as  self-hardening  is  that 
selected. 

As  has  been  said  in  the  observation  on  the  form  and  qualities  of 
tools,  a  great  deal  depends,  not  only  on  the  kind  of  metal  worked, 
but  also  on  the  quality  of  the  particular  kind  that  is  to  be  machined. 

With  the  old  form  of  tools  made  from  the  old  carbon  steels, 
cast  iron  was  turned  at  a  speed  of  from  20  to  25  feet  per  minute; 
soft  steel,  25  to  30  feet;  wrought  iron,  35  to  45  feet;  and  ordinary 
brass  at  from  50  to  100  feet. 

With  the  present  tools  and  methods  such  speeds  are  considered 
child's  play,  and  the  speeds  at  which  different  materials  are  turned, 
assuming  a  medium  grade  of  metal,  will  more  likely  be  given  as 

Soft  Cast  Iron 50  to  60  feet. 

Hard  Cast  Iron 20  to  40 

Hard  Cast  Steel 30  to  40 

Soft  Machine  Steel 30  to  40 

Hard  Machine  Steel • 20  to  30 

Wrought  Iron 35  to  45 

Tool  Steel,  Annealed 20  to  30 

Tool  Steel,  not  Annealed 15  to  20 

Soft  Brass 110  to  130 

Hard  Brass 90  to  110 

Bronze 60  to  80 

Bronze,  Gun  Metal  40  to  60 

Grey  or  Red  Fiber 40  to  60 

The  feeds  will  not  vary  in  the  same  proportion  as  the  speeds, 
or  in  fact  bear  any  fixed  relation  to  them. 

A  prominent  writer  on  this  subject  says  that:  "An  important 
point  is,  that  other  conditions  being  equal,  the  increase  of  speed 
involves  a  diminution  of  feed.  Hence  it  is  not  possible  to  reduce 
the  question  of  speeds  and  feeds  to  formulae,  or  tables." 

This  is  hardly  correct  as  to  the  fact  of  the  inverse  relation  of 
speeds  and  feeds  under  varying  circumstances,  as  the  same  author 
admits  further  on  by  saying:  "Each  class  or  job  must  be  settled  by 


LATHE  TOOLS,   HIGH-SPEED  STEEL,  ETC.  233 

itself  in  the  practice  of  any  given  shop."  He  might  have  said,  with 
each  different  material,  and  as  to  whether  it  is  a  roughing,  sizing, 
or  finishing  cut. 

Some  practical  observations  in  point  may  not  be  amiss,  as  they 
are  taken  from  actual  practice  and  may  be  held  as  good  mechanical 
data,  with  the  use  of  high-speed  steel. 

Roughing  cuts  in  soft  cast  iron  may  be  made  with  a  feed  as 
coarse  as  4  to  5  per  inch,  with  a  tool  whose  leading  corner  is  slightly 
rounded. 

Roughing  cuts  on  soft  machine  steel  forgings,  5  to  8  per  inch. 

Sizing  cuts  on  soft  cast  iron,  12  to  16  per  inch. 

Sizing  cuts  on  soft  machine  steel,  16  to  20  per  inch. 

Finishing  cuts  on  soft  cast  iron,  with  a  narrow-point  tool,  may  be 
from  15  to  25  per  inch. 

Finishing  cuts  on  soft  machine  steel,  with  a  narrow-point  tool, 
20  to  40  per  inch. 

Finishing  cuts  on  soft  cast  iron,  with  a  wide  point,  practically 
straight-faced  tool  with  corners  slightly  rounded,  the  feed  may  be, 
for  soft  cast  iron,  from  1  to  4  per  inch. 

Under  like  circumstances,  for  soft  machine  steel,  the  cut  may 
be  from  4  to  8  per  inch. 

In  these  different  cuts  the  speeds  may  be  substantially  as  stated 
in  the  table  given  above,  except  the  last,  in  which  case  the  speed 
must  be  very  much  slower,  less  than  half  the  speeds  there  given. 

Further  than  these  figures  it  will  be  found  difficult  to  set  down 
a  range  of  speeds  and  feeds  that  will  be  of  any  practical  value.  It 
must  be  left  for  the  superintendents,  foremen,  and  mechanical 
engineers  in  charge  of  work  to  determine  these  facts  and  to  adopt 
such  standards  as  may  be  found  by  actual  experiment  is  most 
satisfactory  under  the  circumstances  and  conditions  governing  the 
work,  and  which  will,  of  course,  include  a  careful  study  of  the 
materials  that  are  to  be  machined. 

The  lubrication  of  tools  has  a  very  considerable  influence  upon 
the  performance  of  lathe  tools,  and  when  used  should  materially 
increase  the  output  of  the  machines  by  permitting  faster  speeds, 
heavier  cuts,  and  greater  feeds.  Lubrication  prevents  the  friction 
that  otherwise  attends  heavy  cutting,  and  therefore  prevents  heat- 
ing to  both  the  work  and  the  tool.  A  steady  stream  flowing  upon 


234  MODERN  LATHE  PRACTICE 

the  cutting-tool  will  tend  to  carry  away  such  heat  as  will,  to  a  cer- 
tain extent,  always  take  place.  Naturally  a  well  lubricated  tool 
will  last  longer  in  proper  condition  for  cutting  than  one  that  is 
not  lubricated,  as  the  friction  of  the  metal  across  the  edge  of  the 
tool  will  be  much  less. 

As  to  the  kind  of  lubricant  to  be  used,  it  will  vary  with  the  kind 
of  metal  to  be  machined  and  its  condition.  Cast  iron  will  require  no 
lubricant.  In  fact  it  is  probable  that  any  kind  of  a  lubricant  would 
be  a  detriment  rather  than  a  help  when  turning  cast  iron.  The 
same  may  be  said  of  ordinary  yellow  brass  castings  and  the  usual 
kinds  of  sheet  brass,  brass  rods  and  tubes.  But  for  bronze,  and 
similar  alloys  containing  a  considerable  portion  of  copper,  it  is 
always  advisable  to  use  a  lubricant,  and,  if  very  hard  and  tough, 
oil  is  the  proper  lubricant.  This  is  also  true  of  the  turning  of 
wrought  iron,  malleable  iron  and  steel,  or  steel  castings. 

As  to  the  kind  of  oil  most  appropriate,  it  is  well  known  that 
lard  oil  leads  all  others.  ,0n  account  of  its  high  price,  this  oil  is 
often  replaced  by  a  mixture  of  lard  and  other  animal  oils  or  fish 
oil.  Mineral  oil  should  not  be  used,  as  it  fails  to  prevent  the  heat- 
ing of  the  work  and  the  tool.  Neither  should  a  mixture  of  animal 
and  mineral  oils  be  made  for  such  a  purpose. 

For  reasons  of  economy  certain  soapy  mixtures  are  sold  for 
these  purposes.  These  are  mixed  with  water  to  a  consistency  to 
flow  freely,  and  often  answer  the  purpose  nearly  as  well  as  oil.  They 
are  more  convenient  and  cleanly  to  use  around  the  machine. 

While  it  is  convenient  to  purchase  these  compounds,  a  good 
one  is  easily  made  by  boiling  for  half  an  hour  or  more  one  half  pound 
of  sal  soda,  one  pint  lard  oil,  one  pint  soft  soap,  and  water  sufficient 
to  make  twenty  quarts.  The  soda  should  first  be  dissolved  in  the 
water,  and  the  oil  and  soap  added  successively  while  the  mixture 
is  hot.  Should  the  mixture  prove  too  thick  to  run  freely  from  a 
drip  can,  or  to  pass  through  a  lubricating  pump,  hot  water  should 
be  added  until  the  desired  consistency  is  obtained. 

Any  purchased  preparation  of  this  kind  that  has  a  tendency  to 
rust  the  cast  iron  parts  of  the  machine  should  be  rejected,  as  it  con- 
tains either  acid  or  an  excess  of  soda,  and  sometimes,  even  potash, 
all  of  which  will  be  detrimental  to  the  work  and  the  machine  as  well 
as  to  the  efficiency  of  the  operations  being  performed.  Trouble 


LATHE  TOOLS,   HIGH-SPEED  STEEL,  ETC.  235 

will  also  be  experienced  with  the  pumps  and  pipes  from  becoming 
clogged  by  the  undissolved  portions  of  the  compound. 

As  to  the  means  used  for  applying  the  lubricant,  the  first  and 
most  simple  is  a  small,  round  bristle  brush.  This  will  answer  well 
enough  for  short  jobs  and  for  small  parts,  but  for  larger  work  is 
rather  a  tedious  process,  requiring  the  constant  attention  of  the 
operator,  and  thus  limiting  him  to  the  work  of  a  single  machine. 
Oil  is  the  lubricant  usually  applied  with  a  brush. 

The  gravity  feed  comes  next  in  order.  This  is  simply  a  "drip 
can,"  which  is  supported  by  a  rod  attached  to  the  rear  of  the  car- 
riage or  compound  rest.  This  can,  holding  a  quart  or  more,  is 
provided  with  a  bent  tube  having  a  faucet,  or  stop-cock,  attached 
at  or  near  the  bottom.  It  is  kept  filled  by  the  operator  pouring 
from  a  tray  under  the  work  such  portions  of  the  lubricant  as  drip 
off  the  work. 

As  a  constant  stream  of  lubricant  is  always  desirable,  however 
large  or  small  it  may  need  to  be,  a  small  pump  is  resorted  to.  A 
small  tank  is  located  under  the  machine  or  near  it,  from  which  the 
pump  draws  its  supply  of  the  lubricant  and  forces  it  up  through  a 
jointed  or  flexible  pipe  to  the  tool.  Its  flow  is  regulated  by  a  stop- 
cock as  in  the  gravity  feed. 

The  tank  is  usually  made  of  cast  iron,  and  is  divided  into  two 
parts  by  a  vertical  plate  reaching  up  to  within  two  or  three  inches  of 
the  top  of  the  tank.  The  lubricant,  as  it  flows  from  the  tool,  carries 
with  it  many  fine  chips  which  flow  into  one  of  these  compartments, 
where  the  chips  fall  to  the  bottom  while  the  lubricant  fills  the  com- 
partment, flows  over  the  vertical  plate  and  into  the  other  com- 
partment where  the  clear  liquid  is  drawn  off  by  the  pump.  This 
method  is  an  improvement  over  the  perforated  metal  plate  or  the 
wire  gauze  strainer. 

Usually  these  pumps  and  tanks  may  be  purchased  independ- 
ently of  a  machine  and  attached  in  any  manner  desired.  As  the 
pumps  are  usually  of  the  rotary  type,  they  may  be  driven  from  a 
small  pulley  on  the  countershaft  of  the  lathe  if  no  special  provision 
for  them  has  been  made  on  the  machine  itself. 

While  these  lubricating  devices  are  usually  more  appropriate 
for  a  turret  lathe  or  similar  machine  than  for  an  ordinary  engine 
lathe,  yet  the  class  of  work  and  the  kind  of  material  to  be  ma- 


236  MODERN   LATHE   PRACTICE 

chined  will  be  the  deciding  factor  more  often  than  the  type  of 
machine. 

It  will  be  often  desirable  to  know  the  power  which  is  being  con- 
sumed in  operating  a  lathe  on  certain  work  for  which  data  is  required. 
For  most  purposes  this  can  be  sufficiently  approximated  by  calcu- 
lating the  power  of  the  lathe  from  the  width  of  the  belt  and  its 
speed  in  feet  per  minute. 

For  such  purposes  it  is  usual  among  mechanical  engineers  to 
consider  that  a  one-inch  belt  traveling  a  thousand  feet  per  minute 
will  transmit  one  horse-power.  This  will  give  us  a  key  to  the  entire 
calculation. 

For  instance,  if  we  have  a  piece  of  work  6  inches  in  diameter, 
we  know  that  for  every  revolution  it  will  move  through  a  distance 
equal  to  its  circumference,  that  is,  18.85  inches.  If  the  cutting 
speed  is  30  feet,  or  360  inches,  we  can  easily  calculate  that  it  must 
make  19.6  revolutions  per  minute.  If  the  back  gear  ratio  of  the 
lathe  is  12,  and  we  are  using  the  back  gears,  the  cone  must  make 
12  times  as  many  revolutions  as  the  piece  of  work,  or  235.2  revolu- 
tions per  minute.  If  the  step  of  the  cone  on  which  the  belt  is 
running  is  19  inches,  it  will  be  practically  60  inches  circumference, 
or  5  feet,  and  therefore  the  belt  speed  will  be  1176.6  feet  per  minute, 
or  1.176  horse-power  for  every  inch  in  width  of  belt.  Now,  assum- 
ing that  the  belt  is  4  inches  wide,  we  shall  be  using  4.7  horse-power, 
if  we  force  the  cut  up  to  the  full  capacity  of  the  belt  to  drive  it. 

This  calculation  is  for  single  belts.  A  double  belt  is  expected 
to  transmit  double  the  power. 

It  would  be  very  interesting  if  we  could  make  a  table  giving  the 
power  required  to  drive  the  lathe  on  all  different  diameters,  for  all 
different  kinds  and  qualities  of  metal,  when  turned  with  all  differ- 
ent forms  of  tools  made  from  all  different  kinds  of  tool  steels,  and  on 
all  different  designs  of  lathes. 

It  would,  however,  be  an  almost  endless  task  and  would  be  of 
very  little  practical  value  when  it  had  been  accomplished.  The 
conditions  as  noted  above,  and  which  are  all  practical,  every-day 
conditions,  are  so  many  and  so  various  that  there  would  be  found 
very  seldom  a  repetition  of  them  in  regular  machine  shop  work. 

To  construct  a  table  that  should  give  the  power  required  for 
different  tools  and  metals  worked  upon  in  a  certain  shop,  it  would 


LATHE  TOOLS,  HIGH-SPEED  STEEL,   ETC.  237 

be  necessary  to  observe  conditions,  ^to  collect  and  record  data,  and 
to  make  calculations  from  these  individual  conditions  and  cir- 
cumstances, in  this  particular  shop.  And  this  table,  while  of  con- 
siderable value  in  this  shop,  and  interesting  to  any  mechanical 
engineer  or  shop  economist,  would  not  be  a  safe  guide  in  any  other 
shop  until  corrected  by  the  data  made  by  an  extended  series  of 
observations,  the  time  and  expense  of  which  would  be  nearly 
equal  to  those  necessary  to  produce  the  original  table. 

These  remarks  are  not  intended  to  discourage  the  desire  to 
obtain  such  data.  It  is  always  commendable  to  search,  observe, 
calculate,  and  "dig  out"  all  these  and  similar  facts  relating  to  the 
performance  of  machine  tools,  and  such  habits  should  be  encouraged 
in  all  who  have  to  do  with  this  work.  No  labor  of  this  kind  is  lost, 
since  every  item  of  such  work  adds  to  the  sum  total  of  our  infor- 
mation and  enriches  the  subject  for  us,  and  gives  us  a  more  secure 
and  confident  hold  on  the  important  questions  involved  in  it. 

A  still  further  reason  for  such  observation  and  the  recording 
of  the  data  thus  obtained  is  the  constant  changing  of  the  design  of 
machine  tools,  the  constant  changing  of  material  to  be  worked  upon, 
the  infinite  number  of  forms  of  the  parts  to  be  machined,  and  the 
thousand-and-one  differing  circumstances  of  their  manufacture. 

A  recent  writer  whose  name,  unfortunately,  is  not  given,  in 
discussing  the  question  of  the  power  required  for  taking  the  cuts 
in  different  metals  and  the  pressure  in  the  tool  says: 

"The  most  complete  information  on  this  subject  is  contained 
in  Flather's  'Dynamometers  and  the  Transmission  of  Power/  in 
which  are  collected  data  from  many  tests  upon  various  kinds  of 
machine  tools.  Since  the  introduction  of  high-speed  steel,  however, 
conditions  have  changed  so  much  that  the  deductions  from  the 
tables  mentioned  would  be  to  a  certain  extent  incorrect.  Probably 
the  most  satisfactory  way  to  determine  the  pressure  on  a  tool  is  to 
obtain  this  from  the  power  required  to  drive  the  machine  when 
cutting.  Knowing  the  horse-power,  if  we  multiply  this  by  33,000 
we  have  the  foot  pounds  per  minute;  dividing  this  by  the  cutting 
speed  in  feet  per  minute  will  give  the  pressure  on  the  tool,  neglect- 
ing the  power  lost  in  overcoming  the  frictional  or  other  resistances 
in  the  machine  itself.  In  tests  upon  high-speed  cutting  steels  at 
the  Manchester  Municipal  School  of  Technology,  to  which  we  shall 


238  MODERN  LATHE  PRACTICE 

presently  refer,  it  was  found  that  the  power  absorbed  by  the  ma- 
chine varied  greatly  with  the  temperature  of  the  bearings  and  also 
with  the  speed.  After  the  bearings  become  warm,  the  oil  is  more 
viscous,  which  makes  an  appreciable  difference;  and  tests  also  show 
that  it  sometimes  requires  more  power  to  run  a  lathe  at  high  speed 
—  as  would  be  the  case  when  filing  a  piece  of  work  —  than  when 
taking  a  heavy  cut  at  a  slow  speed.  These  facts  indicate  the  degree 
of  care  necessary  in  arriving  at  reliable  information  upon  the  sub- 
ject of  your  inquiry. 

Referring  to  the  tests  in  BLatJ^gr'.8  text-book,  we  find  the  follow- 
ing formulas  deduced  from  average  results,  which  give  the  horse- 
power required  to  remove  a  given  weight  of  cast  iron,  wrought 
iron  or  steel : 

For  cast  iron,  horse-power  equals 026  X  W. 

For  wrought  iron,  horse-power  equals 03     X   W. 

For  steel,  horse-power  equals 044  X  W. 

"In  each  of  these  W  is  the  weight  in  pounds  of  the  metal  re- 
moved per  hour. 

"The  most  complete  information  upon  power  required  with 
high-speed  steels  is  that  obtained  by  the  English  tests  at  the  Man- 
chester Municipal  School  of  Technology.  These  are  very  elaborate 
and  cannot  easily  be  summarized,  but  the  following  statement  of 
results  will  answer  our  purpose  and  throw  some  light  on  the  sub- 
ject: 

CUTTING   SOFT  STEEL 

Weight  per  Hour  Horse-Power 

Light  cut 105  3 

'  Heavy  cut 445  15 

CUTTING    CAST   IRON 

Weight  per  Hour  Horse-Power 

Light  cut 42  1.7 

Heavy  cut 198  5.5 

"Applying  Flather's  formulas  to  these  results  we  find  that  for 
steel  the  horse-power  required  would  be  4.6,  instead  of  3,  for  light 
cutting;  and  19.6,  instead  of  15,  for  heavy  cutting.  In  the  case  of 
cast  iron  we  find  the  horse-power  would  be  1.1,  instead  of  1.7,  for 
light  cutting;  and  5.15,  in  place  of  5.5,  for  heavy  cutting.  This 
would  indicate  that  Flather's  formula  for  steel  allows  more  power 
for  soft  steel  than  was  shown  to  be  actually  required  by  the  English 
tests,  and  will  probably  give  ample  power  for  a  considerably  harder 


LATHE  TOOLS,   HIGH-SPEED  STEEL,  ETC.  239 

grade  of  steel.  In  the  case  of  cast  iron  his  formula  appears  to 
apply  very  closely,  but  giving  results  slightly  too  small. 

From  these  comparisons  it  would  seem  that  the  rule  to  multiply 
the  weight  of  metal  removed  per  hour  by  .04  would  give  a  safe 
value  for  the  horse-power  for  both  steel  and  iron. 

Further  examination  of  the  results  of  the  English  tests  shows 
that  with  the  steel  more  metal  was  removed  per  horse-power  when 
taking  a  heavy  cut  than  when  running  at  high  speed  and  taking  a 
light  cut;  while  when  cutting  cast  iron  this  condition  was  reversed. 

It  was  found  that  the  cutting  force  did  not  vary  mucn  with  the 
speed,  because  at  high  speed  the  cuts  were  light  while  at  low  speed 
the  cuts  were  deeper  and  taken  with  a  heavier  feed.  The  pressure 
on  the  tool  increased  very  rapidly  as  the  tool  became  dull;  but 
when  the  tool  was  in  good  cutting  condition  the  following  pressures 
were  recorded: 

Tons 

For  soft  fluid  compressed  steel 115 

For  medium  fluid  compressed  steel 108 

For  hard  fluid  compressed  steel 150 

Tons 

For  soft  cast  iron 51 

For  medium  cast  iron 84 

For  hard  cast  iron 82 

"It  will  be  noted  in  reviewing  these  pressures  that  those  for 
steel  appear  to  be  a  little  irregular,  but  they  are  recorded  in  the 
results  of  the  experiments  cited." 

This  interesting  subject  might,  with  profit,  be  pursued  much 
further  and  such  investigation  is  earnestly  recommended  to  the 
seeker  after  facts  in  this  respect;  but  the  limits  of  space  will  not 
permit  a  more  elaborate  exposition  in  this  chapter. 


CHAPTER  XII 

TESTING   A   LATHE 

i 

Prime  requisites  of  a  good  lathe.  Importance  of  correct  tests.  The  author's 
plan.  Devices  for  testing  alignment.  Using  the  device.  Adjustable 
straight-edge.  Development  of  the  plan.  Special  tools  necessary. 
Proper  fitting-up  operations.  Leveling  up  the  lathe  for  testing.  An 
inspector's  blank.  The  inspector's  duties.  Testing  lead  screws.  A 
device  for  the  work.  A  micrometer  surface  gage.  Its  use  in  lathe 
testing.  Proper  paper  for  use  in  testing.  Test  piece  for  use  on  the 
face-plate.  Testing  the  face-plate.  A  micrometer  straight-edge. 
Allowable  limits  in  testing  different  sized  lathes.  Inspection  report 
-  on  a  lathe.  Value  of  a  complete  and  accurate  report. 

BEFORE  entering  upon  the  consideration  of  the  work  of  the 
lathe  in  all  its  varied  phases  and  by  the  different  methods  that  are 
appropriate  for  the  many  classes  of  work  with  which  we  have  to 
deal,  it  would  seem  proper  to  discuss  the  methods  of  testing  the 
lathe  to  ascertain  its  condition  before  putting  work  upon  it. 

In  so  doing  we  shall  be  able  to  direct  attention  to  some  of  the 
prime  requisites  of  a  good  lathe  and  how  to  ascertain  whether  the 
particular  lathe  in  question  possesses  them  or  not.  We  should 
know  whether  the  main  spindle  is  exactly  parallel  with  the  V's  or 
not,  both  in  a  horizontal  and  a  vertical  plane;  to  know  whether 
the  carriage  is  at  exactly  right  angles  to  the  V's  or  not;  to  know 
whether  the  head  center  and  the  tail  center  are  exactly  in  line  or 
not;  and  so  on  through  the  many  requisite  features  of  a  good  lathe; 
•one  that  will  "turn  straight,  face  flat  and  bore  true." 

The  plan  that  will  be  given  and  the  tools  and  implements  used 
were  devised  by  the  author,  who  used  them  in  testing  hundreds  of 
lathes  and  found  them  accurate  and  practical,  and  confidently 
recommends  them  to  any  mechanic  having  such  duties  to  perform 
and  a  desire  to  perform  that  duty  in  the  best  and  most  accurate 

240 


TESTING  A  LATHE 


241 


manner,  and  to  make  the  reports  on  the  machines  he  tests  of  such 
a  nature  as  to  command  the  confidence  and  respect  alike  of  manu- 
facturer, purchaser,  and  user. 

At  this  time,  when  such  extreme  accuracy  in  machine  tools 
is  demanded,  when  it  may  be  said  that  the  machine  tool  that  could 
be  sold  as  a  fairly  good  tool  ten  or  even  five  years  ago  could  scarcely 
be  given  away  now;  when  a  buyer  critically  tests  every  require- 
ment of  the  machine  he  buys,  and  oftentimes  almost  literally  dis- 
sects it,  it  becomes  necessary  to  adopt  such  methods  and  to  provide 
such  appliances  as  will  insure  a  practical  demonstration  of  its 
accuracy.  Although  the  lathe  is  the  oldest  known  machine  tool 
we  have,  we  are  far  from  knowing  all  its  capabilities  and  possi- 
bilities as  yet,  and  each  year  finds  some  added  good  points  brought 
out  by  the  many  workers  in  the  field. 


FIG.  195.  —  Testing  Alignment  of  Lathe  Centers. 

But  whatever  may  be  its  special  form  or  construction  it  becomes 
a  matter  of  vital  importance  to  practically  test  it  before  it  leaves 
the  hands  of  the  manufacturer. 

And  that  condition  or  those  qualities  which  are  important  to 
the  builders  of  machine  tools  are  equally  important  to  the  purchaser 
who  "pays  good  money  and  expects  a  good  machine."  The  suc- 
cess of  the  mechanic  who  runs  the  machine,  and  the  officials  under 
whom  he  works,  is  a  matter  that  has  its  important  bearing  upon  the 
question,  since  we  cannot  expect  a  high  degree  of  efficiency  with- 
out good  machines. 

Therefore  the  proper  appliances  for  making  accurate  tests  of 
lathes  are  here  presented. 

Figure  195  shows  the  general  construction  of  the  testing  device, 
as  applied  to  a  lathe,  for  ascertaining  the  alignment  of  the  head  and 


242 


MODERN    LATHE   PRACTICE 


tail  spindles.  An  arbor,  A,  is  preferably  constructed  of  thick  steel 
tubing  with  hardened  steel  plugs  fitted  to  and  forced  into  the  ends, 
which  have  been  previously  bored  out.  This  arbor  is  ground  true 

and  should  be  from  4  to  6 
inches  longer  than  the  di- 
ameter of  the  largest  face- 
plate to  be  tested. 

Upon  the  arbor  is  accu- 
rately fitted  a  hardened  and 
ground  collar  B.  At  the  end 
of  the  arbor  next  to  the  face- 
plate the  plug  has  a  mortise  a, 
made  square  at  one  end  and 
at  an  angle  at  the  other,  as 
shown  in  Fig.  196.  At  the 

FIG.  196.  —  Details  of  the  Testing  Bar.     angled  end  is  fitted  a   key  6, 

with  the  usual  projections,  to 

prevent  it  from  dropping  out,  and  controlled  by  the  thumb-screw 
c.  Passing  through  the  mortise  a  is  a  bar  C,  carrying  at  its  outer 
end  a  micrometer  screw  device,  represented  in  detail  in  Fig.  197. 
This  consists  of  a  bar  D,  of 
a  size  convenient  to  hold 
in  the  tool-post  of  the 
lathe  as  well  as  in  the 
slotted  end  of  the  bar  C, 
where  it  is  clamped  by  the 
thumb-screw  k. 

Pivoted  to  the  bar  D  is 
the  curved  bar  E,  having 
pivoted  to  it  the  block  F, 
which  carries  the  micro- 
meter screw  G,  operated 
in  the  usual  manner.  The 
knurled  thumb-screws  d,  e,  fix  these  joints  in  any  desired  position. 
The  use  of  this  apparatus  is  as  follows:  Place  the  arbor  in  the 
lathe,  slide  the  collar  B  up  near  the  mortise  a,  clamp  the  micro- 
meter device  in  the  tool-post  in  the  position  shown  in  the  upper 
figure  in  Fig.  198,  and  bring  the  point  of  the  micrometer  screw 


FIG.  197.  —  Micrometer  in  Position  to  Test. 


TESTING  A  LATHE 


243 


down  upon  the  collar  B,  rotating  the  latter  slightly  to  get  the  pres- 
sure just  right.     Slide  the  collar  B  to  near  the  tail-stock,  move  the 
carriage   down  opposite  to  it  and 
note  if  the  micrometer  screw  rests 
upon  the  collar  as  before.     If  not, 
note  on  the  graduations  of  the  mi- 
crometer the  amount  that  the  tail 
spindle  is  high  or  low. 

It  is  assumed  that  the  centers 
have  previously  lined  fairly  well 
sidewise.  To  set  them  accurately 
the  same  method  as  above  is  used, 
setting  the  micrometer  device  as 
shown  in  the  lower  figure  in  Fig. 
198. 

Supposing  that  the  centers  of 
the  lathe  have  been  found  to  line 
vertically  and  horizontally  correct, 
we  now  desire  to  know  if  the  back 


FIG.  198.  —  Testing  Alignment  of 
the  Tail-Stock  Spindle. 


box  of  the  head  spindle  is  set  in  exact  prolongation  of  the  line  of 
centers.  Place  the  bar  C  in  position  and  clamp  the  micrometer 
device  in  it,  as  shown  in  Fig.  195.  Slowly  revolve  the  tram  device 
thus  arranged,  setting  the  micrometer  screw  to  the  nearest  point  in 
contact  with  the  face-plate.  Continue  the  revolution  and  with  the 
micrometer  screw  ascertain  the  exact  variations  of  the  face-plate 


FIG.  199.  —  Straight-Edge  for  Testing  the  Cross  Slide. 

from  a  perfect  right  angle  with  the  line  of  centers.  Having  deter- 
mined the  accuracy  of  alignment  of  the  lathe,  we  now  desire  to  test 
its  accuracy  of  facing  —  whether  it  will  face  up  a  piece  concave, 
convex,  or  exactly  true,  and  to  note  the  extent  of  the  variation. 
Figure  199  shows  an  adjustable  straight-edge  for  this  purpose. 


244  MODERN  LATHE  PRACTICE 

H  is  a  permanent  straight-edge  used  only  for  adjusting  the  one 
applied  to  the  face-plate.  This  is  shown  at  K  and  has  its  lower 
edge  formed  as  shown  in  the  section  at  the  right,  and  has  three 
blocks,  I,  m,  and  n,  sliding  upon  it  and  fixed  at  any  point  by  the 
thumb-screw  t.  These  blocks  are  set  at  such  distances  apart  as 
will  accommodate  the  size  of  the  face-plate  to  be  tested.  The 
block  n  carries  a  fixed  point,  about  -f$  of  an  inch  in  diameter  at  the 
point.  The  block  /  carries  a  plain  screw  point  s,  used  to  adjust  the 
device  so  that  the  micrometer  screw  r  of  the  block  m  may  be  ad- 
justed at  zero.  To  adjust  these  set  the  micrometer  screw  at  zero 
and  then  bring  the  screw  s  up  or  down  till  all  these  points  rest 
properly  on  the  permanent  straight-edge. 

To  apply  the  device  to  the  face-plate  to  be  tested  the  surface 
w  is  placed  downward  on  a  short  arbor,  taking  the  place  of  the 
head  center  of  the  lathe  and  projecting  about  6  inches  from  the 
face-plate.  This  not  only  furnishes  a  convenient  support,  but  keeps 
the  contact  points  at  right  angles  to  the  face-plate.  Keeping  the 
points  of  the  block  n  and  the  adjusting  screw  s  in  contact  with  the 
face-plate,  the  micrometer  screw  r  may  be  set  to  the  convexity 
or  concavity  of  the  plate,  and  the  error  read  on  the  micrometer 
graduations  p,  in  thousands  of  an  inch,  or  even  much  finer. 

A  subject  thus  important  will  necessarily  have  its  developments 
and  these  should  be  made  by  actual  experience  in  a  practical 
manner.  In  developing  these  methods  of  testing  a  lathe,  further 
instruments  were  necessary  and  are  therefore  described.  In  some 
cases  where  there  are  two  methods  of  test,  one  of  these  was  used 
and  in  some  cases  the  other.  Again,  both  were  used  and  checked 
against  each  other. 

The  special  tools  necessary  for  determining  the  accuracy  of  an 
engine  lathe  must,  of  course,  be  accurate  and  reliable,  but  they 
need  not  for  this  reason  be  elaborate  or  expensive,  as  the  illustra- 
tions accompanying  this  article  will  readily  show.  Their  descrip- 
tion and  use  will  be  fully  explained  as  the  process  of  inspection 
is  proceeded  with  in  the  matter  which  follows. 

It  is  assumed  that  the  lathe  bed,  as  well  as  the  head-stock,  tail- 
stock  and  carriage,  have  been  properly  planed,  the  V's  shaped  to  the 
proper  angle,  and  that  the  V's  of  the  bed  have  been  scraped  straight 
and  true,  removing  as  little  of  the  metal  as  possible.  The  head- 


TESTING  A  LATHE  245 

stock,  tail-stock,  and  carrriage  should  now  be  carefully  scraped  to 
fit  the  V's  of  the  bed.  Their  fair  bearing  may  be  easily  ascertained 
by  rubbing  on  a  little  of  a  mixture  of  the  dry,  red  pigment  com- 
monly known  among  painters  as  "  princess  red,"  or  some  similar 
dry  color,  mixed  with  a  small  portion  of  any  oil  that  may  be  con- 
venient. The  above  color  will  be  found  to  have  this  convenience: 
it  will  show  almost  black  where  the  pressure  is  very  severe  and  cor- 
respondingly lighter  where  the  contact  is  less  perfect.  The  scrap- 
ing should  be  continued  until  the  contact  spots  do  not  exceed  f 
inch  from  center  to  center,  and  the  inspector  should  assure  himself 
of  this  fact  before  these  parts  are  finally  fixed  in  position. 

The  carriage  should  be'  run  back  and  forth  along  the  length  of 
the  bed  to  detect  any  slight  curves  that  the  bed  may  have  taken 
since  it  was  planed,  and  if  any  are  found  they  should  be  corrected 
by  scraping.  Of  course  the  bed  should  be  carefully  leveled  up  and 
kept  so  during  the  time  this  scraping  and  fitting  is  going  on. 

When  the  lathe  is  finally  "set  up"  or  erected,  great  care  should 
be  taken  to  have  it  in  as  firm  a  foundation  as  is  possible,  and  this 
requirement  becomes  all  the  more  important  as  the  lathe  is  larger 
and  heavier.  The  bed  should  be  carefully  leveled  both  longitudi- 
nally and  transversely,  applying  the  level  to  the  tops  of  the  V's  at 
points  not  over  four  feet  apart  for  large  and  heavy  lathes,  and 
not  over  three  feet  for  small  and  medium  sized  ones.  If  this 
is  not  carefully  attended  to  it  will  be  difficult  to  determine  with 
any  reasonable  degree  of  accuracy  whether  or  not  the  lathe  will 
bore  truly,  as  a  slight  change  in  the  tops  of  the  V's,  throwing 
them  out  of  a  true  plane,  will  defeat  the  test. 

Neither  can  proper  tests  by  means  of  the  carriage  be  made  if 
the  V's  on  the  bed  are  not  so  carefully  leveled  up  as  to  be  correctly 
in  the  same  plane. 

Before  proceeding  to  further  describe  this  system  of  lathe  test- 
ing, attention  is  called  to  the  accompanying  blank  report  for 
properly  recording  the  results  of  the  inspection.  It  will  be  noticed 
that  it  is  quite  thorough,  but  a  long  experience  in  machine  tool 
work  brings  us  to  the  conclusion  that  there  is  not  a  superflu- 
ous observation  or  requirement  in  it.  And  it  is  recommended 
that  lathe  builders  send  a  signed  copy  of  this  report  to  the  cus- 
tomer who  purchases  the  lathe,  for  his  information  and  guidance 


246 


MODERN   LATHE   PRACTICE 


in  testing  the  lathe  for  himself  when  he  has  it  set  up  in  his  own 
shop. 

There  are  many  items  of  an  inspector's  duty  not  here  enumerated 
which,  in  a  shop  properly  arranged  and  managed,  will  have  been 
attended  to  as  the  parts  are  being  made  and  assembled.  This 
relates  only  to  the  performance  and  outward  condition  of  the  lathe 
when  ready  for  its  final  inspection. 

Lead  screws  should  be  tested  before  they  are  put  into  the  lathe 
of  which  they  are  to  become  a  part.  They  should  be  held  on  centers 


GRADUATIONS  50  TO  l' 


FIG.  200.  —  Device  for  Testing  Lead  Screw  Threads. 

and  may  be  tested  for  accuracy  of  thread  by  the  device  shown  in 
Fig.  200,  in  which  A  is  the  lead  screw  to  be  tested,  upon  which  is 
applied  the  main  frame  B  of  the  device,  supported  by  its  capped 
bearings  C,  D,  the  former  just  fitting  over  the  top  of  the  thread  and 
the  latter  having  either  a  babbitt  metal  lining  cast  upon  the  thread 
or  being  provided  with  a  split  sleeve  in  which  this  babbitt  nut  is 
cast.  The  latter  arrangement  is  best,  particularly  when  lead  screws 
of  different  pitches  or  different  diameters  are  to  be  tested. 

In  case  of  different  diameters,  the  bearing  C  should  also  be 


TESTING   A   LATHE 


247 


bored  large  enough  to  allow  of  a  suitable  bushing  being  introduced. 
The  frame  B  of  the  device  is  extended  to  the  right  to  form  a  grooved 
support  for  the  adjustable  arm  E,  secured  by  the  bolt  e  and  ad- 
justed by  the  screw  /.  This  arm  is  extended  to  form  a  graduated 
segment  at  g.  Pivoted  in  the  arm  E  is  the  indicating  lever  F, 
whose  front  end  is  formed  to  fit  the  thread  of  the  lead  screw  A,  and 
to  whose  rear  end  is  fixed  the  indi- 
cating arm  G,  whose  point  rests  on 
the  graduations  at  g. 

The  leverage  and  graduations  are 
so  arranged  that  thousandths  of  an 
inch  are  indicated  by  lines,  and  a 
much  smaller  fraction  may  be  readily 
perceived.  In  using  this  device  that 
portion  of  the  frame  B  between  the 
bearings  C,  D,  rests  on  the  top  of  the 
compound  rest,  the  lathe  being  ar- 
ranged for  the  same  pitch  as  the  lead 
screw  to  be  tested.  The  screws  hold- 
ing down  the  caps  of  the  bearings 
C,  D,  are  set  up  just  close  enough  to 
insure  a  proper  fit.  The  object  of 
using  a  babbitted  nut  in  the  bearing 
D  and  applying  the  indicating  lever 
F  at  some  distance  from  it  is  three- 
fold. The  influence  of  the  lead  screw 
of  the  lathe  in  use  is  not  felt,  there  is 
very  little  friction  on  the  point  of 
the  indicating  lever  F,  and  the  rela- 
tive inequalities  of  the  thread  of  the 
lead  screw  to  be  tested  are  rendered 
more  obvious. 

Another  very  important  and  useful  instrument  in  lathe  testing 
is  the  micrometer  surface  gage,  which  is  shown  in  Figs.  201  and 
202,  in  which  all  principal  dimensions  are  given. 

The  base  A  is  of  cast  iron,  the  supporting  rod  B  and  the  pointer 
b  are  of  Crescent  steel  drill  rod,  and  the  other  parts  (excepting  the 
spiral  spring)  are  of  tool  steel.  Its  construction  is  readily  under- 


FIG.  201.  —  Micrometer  Surface 
Gage. 


248 


MODERN   LATHE  PRACTICE 


stood  from  the  drawings,  special  attention  being  called  to  the 

arrangement  for  securing  the  pointer  b,  as  shown  in  section  in  Fig. 

202,  by  means  of  the  conically  formed  thumb-nut  G,  its  clamping 

bolt  H,  and  the  conically  formed  receiver. 

The  blocks  C,  D,  are  connected  by  the  rod  K,  whose  lower 

end  is  fixed  in  the  block  D  and 
whose  upper  end  passes  up 
through  the  block  C,  where  it  is 
cut  with  a  thread  40  to  the  inch, 
and  provided  with  a  graduated 
thumb-nut  L,  by  means  of  which 
we  may  read  thousandths  of  an 
inch,  and  even  the  quarters  of 
that  fraction  are  readily  de- 
termined. 

C©  1 1     "jji  Blocks  C  and  D  are  forced 

F|  apart  by  the  spiral  spring  sur- 

rounding the  rod  K.  In  the  use 
of  this  device  the  block  D  is  se- 
cured by  the  thumb-screw  F. 
The  pointer  b  is  then  brought 
down  near  the  work  and  is  se- 
cured by  the  thumb-nut  G.  The 
thumb-nut  E  is  now  tightened 
just  enough  to  hold  it  firmly,  and 
the  final  adjustment  made  by 
means  of  the  graduated  thumb- 
nut  L. 


FIG.  202.  —  Details  of  Micrometer 
Surface  Gage. 


The  lathe  being  ready  for  testing  and  the  face-plate  having  been 
faced  off,  we  begin  with  the  test  for  alignment,  as  shown  in  Fig.  203, 
which  is  a  rear  elevation  of  a  lathe  ready  to  be  tested,  and  Fig.  204 
a  plan  of  the  same. 

To  ascertain  the  vertical  alignment  of  the  head  spindle  we  place 
an  accurately  ground  and  properly  fitted  test  bar  A  in  the  center 
hole  of  the  head  spindle  and  place  the  micrometer  surface  gage  on 
the  lathe  V's  as  shown  in  Fig.  203,  first  applying  the  pointer  b  at  a 
point  near  the  face-plate  and  then  near  the  outer  end  of  the  test 
bar,  as  shown  by  dotted  lines,  using  the  micrometer-adjusting  nut 


TESTING  A  LATHE 


249 


L  to  ascertain  the  difference,  if  any.  To  render  the  touch  of  the 
pointer  more  sensitive  a  slip  of  paper  should  be  drawn  carefully 
between  the  test  bar  and  the  pointer.  The  best  paper  for  this 
purpose  is  a  hard  calendered  linen  typewriter  paper,  three  thou- 
sandths of  an  inch  thick,  as  this  paper  runs  very  uniform  in  thick- 
ness. 


L  T 


FIG.  203.  —  Rear  Elevation  of  Lathe  being  Tested  for  Alignment  of 
Head-Stock  and  Tail-Stock  Spindles. 

If  the  inner  and  outer  V's  of  the  lathe  are  not  of  the  same  height, 
a  parallel  bar  should  be  laid  across  the  V's  and  the  micrometer 
surface  gage  placed  upon  it.  In  any  event  much  care  should  be 
exercised  to  be  sure  that  the  gage  base  sits  fairly  on  its  support, 
as  a  slight  scratch,  or  a  burr,  or  the  least  bit  of  dirt,  will  defeat  the 
object  of  the  test. 


lilt 


FIG.  204.  —  Plan  of  Lathe  being  Tested  for  Alignment  of  Head-Stock 
and  Tail-Stock  Spindles. 

The  vertical  alignment  of  the  tail  spindle  is  tested  in  the  same 
manner,  as  shown  in  Fig.  203.  It  may  also  be  tested  by  bringing 
the  pointer  down  on  the  spindle  itself,  when  it  is  run  back  into  the 
tail-stock,  and  again  when  it  is  run  out  as  far  as  it  will  go.  It 
sometimes  happens  that  we  shall  get  a  different  result  by  sliding 
the  tail-stock  to  a  different  position  on  the  bed.  In  this  case  we 
will  probably  find  some  inequality  in  the  V's  to  account  for  it. 


250 


MODERN   LATHE   PRACTICE 


To  test  the  lateral  alignment  of  the  head  spindle,  a  bar  of  the 
size  of  the  ordinary  lathe  tool,  with  its  front  end  bent  to  a  right 
angle,  and  provided  with  a  micrometer  head,  is  placed  in  the  com- 
pound rest  as  shown  in  Fig.  204,  and  the  reading  made  in  a  manner 
similar  to  the  last  test.  The  lateral  alignment  of  the  tail  spindle 
is  tested  in  a  similar  manner,  moving  the  carriage  to  the  desired 
point. 

To  ascertain  the  accuracy  of  the  center  hole  in  the  head  spindle, 
we  may  use  our  micrometer  at  the  end  of  the  test  bar  A,  as  shown 
in  Fig.  204,  and  by  turning  the  spindle  a  quarter  of  a  turn  at  each 
reading  we  may  ascertain  its  accuracy  with  certainty. 

The  foregoing  tests  would  seem  to  be  sufficient  to  insure  the 
correct  boring  of  a  job  on  this  lathe.  But  it  must  not  be  forgotten 
that  the  error  detected  by  the  test,  as  shown  in  Fig.  204,  will  be 
doubled  in  boring  a  piece  of  work. 

Therefore  the  best  test  of  ascertaining  the  boring  quality  of  the 
lathe  will  be  by  bolting  a  cast  iron  test  piece  to  the  face-plate,  as 
shown  in  Fig.  205.  A  very  light  cut  is  taken  off  from  the  raised  por- 
tions C,  C,  and  measure- 
ments taken  with  the 
micrometer.  This  test  for 
boring  will  be  much  more 
conclusive  than  attempt- 
ing to  actually  bore  a  piece 
of  work,  owing  to  the 
difficulty  of  making  any 
boring  tool,  held  in  a  com- 
pound rest,  bore  the  same 
sized  hole  as  both  ends  of 
a  piece  from  12  to  30  inches 


FIG.  205.  —  Test  Piece  for  ascertaining  if 
Head-Stock  Spindle  is  Parallel  with  the  Vs. 


long.    In  this  connection  a  diagram  and  all  necessary  dimensions 
for  test  pieces  for  different  sized  lathes  are  given  in  Fig.  207. 

To  test  for  the  concavity  or  the  convexity  of  the  face-plate  it  is 
usual  to  use  an  ordinary  straight-edge  and  three  slips  of  paper. 
This  may  be  nearly  correct,  but  we  have  no  means  of  knowing  the 
exact  amount  of  the  error.  For  this  reason  the  micrometer  straight- 
edge shown  in  Fig.  206  was  designed.  The  stock  A  is  slotted  at 
each  end,  and  in  these  slots  are  secured  the  outer  points  B,  B,  ca- 


TESTING  A  LATHE 


251 


FIG.  206.  —  Micrometer  Straight-Edge  for 
Testing  Face-Plates. 


pable  of  being  adjusted  to  different  diameters  of  face-plates,  and 
are  secured  by  the  thumb-nuts  C,  C.  The  center  point  D  is  a  microm- 
eter head,  operated  by  the  usual  milled  head  E. 

In  using  this  straight-edge  it  is  first  turned  up  on  a  fixed  straight- 
edge and  the  center  point 
adjusted  so  that  the  three 
points  are  accurately  in 
line,  using  slips  of  paper 
to  ascertain  this  correctly. 
The  test  bar  is  now  placed 
in  the  head  center  hole 
and  the  flat  space  a  of  the 
straight-edge  laid  upon  it  for  support. 

Slips  of  paper  are  now  introduced  between  the  points  and  the 
face-plate.  The  micrometer  position  is  noted,  and  then  adjusted 
to  hold  the  center  slip  of  paper,  when  a  second  reading  will  give 
convexity  or  concavity  of  the  face-plate. 

The  allowable  limits  of  va- 
riation of  lathes  may  be  about 
as  follows,  viz.:  14  to  20-inch 
swing  lathes,  inclusive,  .0005 
inch;  22  to  28-inch  swing 
lathes,  inclusive,  .001  inch;  30 
to  48-inch  swing  lathes,  inclu- 
sive, .002  inch;  lathes  larger 
than  these,  .003  inch. 

These  limits  apply  to  all 
the  foregoing  tests,  the  dis- 
tances between  testing  points 
to  be  as  given  in  the  table, 
Fig.  207.  It  should  be  under- 
stood that  no  convexity  of  a 
face-plate  is  to  be  allowed. 

The  various  other  points  of 
inspection  as  given  in  the  re- 
port blank  will  need  no  special  explanation,  certainly  not  to  men 
accustomed  to  this  class  of  of  ttimes  trying  and  delicate  work. 


Swing  of 

Lathes 


w'W.ie 


is"  and  20M 


22l!and  2411 


32M»nd  36" 


42"and.48" 


OOrand  72" 


a* 


24H 


275-4 


IX 


UN 


Hi 


814 


IN 


2% 


FIG.  207.  —  Table  giving  Form  and 
Dimensions  for  Test  Pieces  shown  in 
Fig.  205. 


252  MODERN   LATHE   PRACTICE 

INSPECTION  REPORT  ON  LATHE 

NAME  OF  COMPANY 

Inspection  No Date,  inspection  commenced 

Size  of  Lathe T Date,  inspection  completed  . 

Lathe  prepared  for  inspection  by 

Special  features  of  Lathe 


1.  Level  longitudinally 

2.  Level  laterally 

3.  Swing  over  the  V's 

4.  Swing  over  the  carriage 

5.  Distance  between  centers 

6.  Fitting  of  head-stock  on  V's 

7.  Fitting  of  tail-stock  on  V's 

8.  Fitting  of  carriage  on  V's 

9.  Bores,  large  at  inner  end 

10.  Bores,  large  at  outer  end 

11.  Faces concave 

12.  Head  center,  high  at  outer  point. 

13.  Head  center,  low  at  outer  point  . 

14.  Head  center,  to  the  front  at  outer 

point 

15.  Head  center,  to  the  rear  at  outer 

point 

16.  Tail  center,  high  at  outer  point.. 

17.  Tail  center,  low  at  outer  point... 

18.  Tail  center,  to  the  front,  at  outer 

point 

19.  Tail  center,  to  the  rear  at  outer 

point 


20.  Center  hole  in  head  spindle 

21.  Back  gears,  run 

22.  Second  back  gears,  run 

23.  Internal  gear,  runs 

24.  Feed  gears  on  head,  run 

25.  Compound  rest  bevel  gears,  run  . 

26.  Apron  gears,  run 

27.  Rack  pinion  works 

28.  Lost  motion  in  apron  gears 

29.  Reverse  device  in  apron 

30.  Lead  screw 

31.  Tail  spindle  screw  fits 

32.  Cross  feed  screw  fits 

33.  Comp.  rest  screw  fits 

34.  Appearance  of  scraped  surfaces.. 

35.  Appearance  of  polished  surfaces  . 

36.  Finished  corners  properly  rounded 

37.  Width  on  cone  steps 

38.  Change-gears   fit   studs  properly. 

39.  Wrenches  fit  properly 

40.  Squares  for  wrenches  of  uniform 

sizes . . 


Remarks 


Signed. 


Inspector, 

A  critical  examination  of  the  above  list  of  questions  is  invited 
in  order  to  fully  appreciate  the  value  of  such  a  thorough  system  of 
tests  both  to  the  concern  who  builds  the  lathe  and  to  he  who  pur- 
chases and  uses  it.  Such  a  system  will  give  a  healthy  tone  to  the 
workmanship  of  the  shop,  and  when  fairly  met  by  the  conditions  of 
the  machines  turned  out  will  be  a  source  of  pride  to  the  workmen 
employed  in  it. 


TESTING  A  LATHE  253 

On  the  other  hand  it  will  give  a  feeling  of  confidence  and  se- 
curity to  the  purchaser,  who  will  naturally  feel  that  he  is  getting 
full  value  for  the  money  he  has  spent  in  purchasing  the  machine. 
Further,  the  lathe  going  into  the  shop  with  such  prestige  will 
naturally  be  looked  upon  as  a  good  machine,  and  more  than  the 
usual  amount  of  care  will  be  bestowed  upon  it  and  upon  the 
product  which  it  turns  out. 


CHAPTER  XIII 

LATHE   WORK 

The  use  of  hand  tools.  Simple  lathe  work.  Lathe  centers.  Care  in  reaming 
center  holes.  Locating  the  center.  Use  of  the  center  square.  Angle  of 
centers.  Lubrication  of  centers.  Centering  large  pieces  of  work. 
Driving  the  work.  Lathe  dogs.  The  clamp  dog.  The  die  dog.  The 
two-tailed  dog.  Lathe  drivers.  Using  dogs  on  finished  work.  Clamp 
dog  for  taper  work.  Bolt  dog.  Methods  of  holding  work  that  cannot 
be  centered.  Center  rest  work.  Chuck  work.  Use  of  face-plate  jaws. 
Lathe  chucks.  The  Horton  chuck.  The  Sweetland  chuck.  The 
Universal  chuck.  Face-plate  jaws.  A  Horton  four-jaw  chuck.  The 
Horton  two-jaw  chuck.  A  Cushman  two-jaw  chuck.  Chucking  cylin- 
drical work.  Inside  chucking.  Chucking.  Chucking  work  supported 
in  a  center  rest.  Pipe  centers.  Mortimer  Parker's  improved  forms 
of  pipe  centers.  Spider  centers.  Ball-thrust  pipe  centers.  Lathe 
arbors  or  mandrels.  Kinds  of  mandrels.  Expanding  arbors  or  man- 
drels. Making  solid  arbors.  The  taper  of  an  arbor.  Hardened  and 
ground  arbors.  The  Greenard  arbor  press.  Its  advantages. 

IN  the  chapter  on  lathe  tools  the  subject  of  hand  tools  was 
purposely  omitted,  as  their  use  has  greatly  diminished  during  the 
past  few  years,  with  the  possible  exception  of  their  employment  on 
small  bench  lathe  work  and  on  some  kinds  of  brass  work,  and  much 
of  the  work  formerly  done  with  hand  tools  is  now  done  in  the 
regular  operations  on  the  turret  lathe,  the  screw  machine,  and  with 
forming  tools  on  ordinary  engine  lathes. 

Such  hand  tools  as  are  still  used  in  a  limited  degree  will  be 
referred  to  in  the  proper  places  in  the  following  description  of 
lathe  work. 

When  the  apprentice  is  first  put  to  work  on  a  lathe  it  will  prob- 
ably be  the  turning  of  a  piece  of  shafting  on  centers,  and  his  first 
duty  will  be  to  center  it,  that  is,  to  drill  and  ream  proper  bearings 
for  the  center.  If  he  is  in  a  modern  shop  the  old  method  of  form- 

254 


LATHE  WORK 


255 


ing  the  center  hole  by  means  of  a  prick-punch  and  a  hammer  will 
not  be  tolerated.  Neither  will  the  practice  which  succeeded  it, 
that  of  drilling  a  small  hole  and  then  spreading  it  out  or  counter- 
sinking it  with  the  center  punch.  The  hole  was  once  drilled  with 
a  "  fiddle-bow  'drill/'  which  was  later  replaced  by  the  geared  breast 
drill,  which  is  very  convenient  for  some  jobs  but  not  a  tool  to  drill 
a  good  center  hole  with. 

Lathe  centers  should  be  accurately  ground  to  an  angle,  at  the 
point,  of  60  degrees.  Center  grinding  attachments  are  provided 
for  this  work  (as  shown  in  the  chapter  on  lathe  attachments), 


FIG.  208.  —  Centering  Lathe  Work. 

which  will  give  a  very  perfect  angle.  Of  course  the  center  has  been 
previously  hardened  so  as  to  stand  the  wear  of  the  revolving  piece 
of  work.  Nevertheless  there  should  be  considerable  care  exercised 
in  drilling  and  reaming  the  center  hole  so  that  it  shall  really  fit  the 
angle  of  the  center.  There  are  various  ways  of  doing  this.  The 
most  convenient  way  is  to  use  for  this  purpose  a  combined  drill  and 
countersink  shown  at  A  in  Fig.  208,  which  will  drill  the  center  hole 
and  countersink  or  ream  it  to  the  proper  angle.  These  are  made 
of  various  sizes  to  adapt  them  to  the  diameter  and  weight  of  the 
work  to  be  centered.  At  B  is  shown  another  and  older  form  of 
center  reamer  which  is  made  by  turning  up  the  tool  to  the  proper 
angle  and  then  cutting  away  the  upper  half  so  as  to  give  a  cutting 
edge. 

The  disadvantage  of  using  this  form  is  that  two  operations  must 


256  MODERN  LATHE  PRACTICE 

be  performed,  that  of  drilling,  and  afterwards  reaming  or  counter- 
sinking. 

To  center  a  piece  of  round  material  it  may  be  first  " scribed"  by 
the  dividers  or  the  hermaphrodite  calipers  (a  caliper  having  one 
regular  caliper  leg  and  one  pointed  one,  similar  to  the  leg  of  dividers), 
which  are  set  approximately  to  the  radius  of  the  piece,  and  three 
or  four  arcs  marked  across  the  previously  chalked  surface,  forming 
a  small  triangle  or  a  square,  within  which  the  first  prick-punch  mark 
is  made.  This  is  followed  by  the  drilling. 

This  may  be  more  quickly  done  by  a  center  square  shown  at 
C,  Fig.  208,  applying  it  as  shown  and  scratching  a  line  across  the 
work,  then  turning  the  work  about  a  quarter  turn  and  scratching 
again  in  the  same  way.  The  intersection  of  these  lines  will  be  the 
center,  which  may  then,  be  marked  with  the  prick-punch  as  before. 

The  use  of  a  centering  machine  will  much  facilitate  the  work 
on  small  and  medium  sized  work.  In  this  machine  the  work  is 
held  in  a  self-centering  chuck,  mounted  on  a  short  lathe  bed  and 
holding  the  piece  of  work  exactly  in  line  with  and  in  front  of  the 
center  drill  and  countersink  shown  at  A,  and  held  in  a  chuck  carried 
by  the  spindle  of  the  machine  which  has  a  head-stock  quite  like 
that  of  an  ordinary  lathe,  and  the  spindle  adapted  to  slide  forward 
in  drilling  the  hole.  By  the  use  of  this  machine  the  center  drilling 
and  countersinking  will  be  in  accurate  alignment  with  the  axis  of 
the  work,  and  with  this  drill  the  angles  will  be  correct,  the  work 
and  the  center  appearing  as  shown  at  D,  in  the  above  engraving. 

Should  the  form  of  a  center  reamer,  or  countersink,  be  too  obtuse 
an  angle  the  effect  will  be  as  seen  at  E,  in  which  it  is  seen  that  the 
center  bears  only  slightly  near  its  point.  It  will  thus  be  worn  out 
of  shape  and  quite  naturally  the  axis  of  revolution  will  change. 

If  the  angle  of  the  center  hole  is  too  acute  the  lathe  center  will 
only  bear  at  the  edge  of  the  hole,  as  shown  at  F,  and  the  tendency 
will  be  to  wear  a  crease  around  the  center  at  this  point,  and  the 
work  will  finally  "run  out,"  that  is,  the  axis  of  revolution  will 
change  as  in  the  last  example. 

Should  the  drill  and  countersink  not  be  in  line  with  the  axis  of 
the  work  the  result  will  be  as  shown  at  G,  and  the  work  will  not 
only  run  out  of  true  in  a  little  time,  but  the  lathe  center  is  likely 
to  be  spoiled. 


LATHE  WORK 


257 


The  proper  lubrication  of  tail  centers  is  important,  otherwise 
the  pressure  will  create  so  much  friction  that  the  center  will  heat 
and  "burn  off."  To  prevent  this  some  centers,  particularly  large 
ones,  have  an  oil  hole  drilled  in  the  point,  which  is  left  large  enough 
for  that  purpose.  This  hole  connects  with  one  at  right  angles  with 
it  and  opening  beyond  or  outside  of  the  end  of  the  work,  and  through 
which  oil  may  be  introduced  while  the  lathe  is  running,  thus  keep- 
ing the  center  always  well  lubricated.  The  plan  is  an  excellent  one 
on  heavy  work,  or  in  fact  on  nearly  all  work  in  lathes  of  24-inch 
swing  and  larger,  and  the  larger  the  center  the  more  benefit  will  be 
found  in  its  application. 


2  3 

FIG.  209.  —  Lathe  Dogs. 

From  these  examples  and  remarks  it  will  be  seen  that  much 
depends  on  making  the  center  holes  of  the  right  form  if  we  expect 
to  produce  a  good  piece  of  turned  work. 

In  centering  large  pieces  of  work  it  is  sometimes  the  custom  to 
hold  one  end  of  the  shaft  or  forging  in  a  chuck  on  the  main  spindle 
of  the  lathe,  and  the  other  end  in  a  steady  rest,  or  center  rest.  The 
lathe  is  started  and  a  pointed  tool  set  in  the  tool-post  is  brought 
against  the  work  and  the  center  scratched  into  it  as  it  revolves. 
This  is  quicker  and  more  accurate  than  the  scribing  method,  par- 
ticularly in  the  case  of  heavy  and  rough  forgings. 

The  piece  of  work  having  been  properly  centered,  we  apply  to 
it  a  dog  which  serves  to  drive  it  and  suspend  it  between  the  centers, 
first  carefully  oiling  the  tail-stock  center  and  setting  it  up  just 
tight  enough  to  hold  the  work  closely  and  without  end  motion. 

Lathe  dogs  are  of  various  kinds.  The  most  common  kind  is 
that  shown  at  1,  in  Fig.  209,  which  is  fixed  to  the  piece  to  be  turned 


258  MODERN   LATHE  PRACTICE 

by  the  set-screw  and  the  work  is  driven  by  the  tail  of  the  dog  enter- 
ing the  driving  slot  in  the  small  face-plate  of  the  lathe.  The  clamp 
dog  shown  at  2  is  useful  for  driving  square  or  flat  pieces,  and  is  also 
frequently  used  for  cylindrical  work,  which  it  is  not  so  liable  to  mar 
as  is  the  set-screw  of  the  first  form. 

At  3  is  shown  another  form  known  as  a  die  dog,  the  jaws  being 
movable  and  closed  up  by  the  set-screw.  The  jaws  being  threaded 
may  be  applied  to  threaded  work  which  is  of  such  form  that  a  dog 
cannot  be  placed  upon  any  part  but  that  which  is  threaded. 

At  4  is  shown  what  is  called  a  two-tailed  dog,  sometimes  used  on 
large  work  and  driven  from  " drivers"  placed  against  the  two  tails. 
These  drivers  may  be  made  for  the  purpose  and  consist  of  a  piece 
of  round  steel  of  sufficient  length  to  reach  from  the  front  of  the  face- 
plate out  to  and  across  the  dog,  and  be  secured  to  the  face-plate 
by  a  cap  screw,  with  a  washer  under  its  head,  and  coming  through 
the  face-plate  from  the  back  and  into  the  end  of  the  driver.  Or  it 
may  have  a  shoulder  and  be  held  by  a  nut. 

More  often,  however,  the  driver  is  a  bolt  long  enough  for  the 
purpose,  with  a  sleeve  made  of  a  piece  of  gas  pipe  or  a  block  of 
cast  iron  with  a  hole  through  it,  which  keeps  the  end  of  the  bolt 
far  enough  to  reach  the  dog. 

In  placing  dogs  on  finished  work  a  piece  of  brass  or  copper  should 
be  put  under  the  points  of  the  set-screws  to  prevent  marring  the 
work.  In  using  the  clamp  dog  at  2  on  finished  work  the  pieces  of 
brass  or  copper  should  also  be  used. 

Various  other  forms  of  dogs  are  used  for  special  work  and  for 
very  large  work ;  as,  for  instance,  two  more  or  less  curved  bars  and 
fastened  together  by  bolts,  somewhat  in  the  form  shown  at  2,  Fig. 
209. 

But  in  all  cases  the  principle  is  the  same,  to  clamp  to  the  piece 
of  work  a  device  having  formed  upon  it  a  projecting  part,  called 
the  tail,  by  which  the  work  may  be  rotated. 

In  some  cases  when  the  clamp  dog  shown  at  2  is  much  used  on 
taper  work  the  heads  of  the  clamp  screws  are  made  in  the  form  of 
eyes,  and  the  upper  cross  bar  or  clamp  bar  has  trunnions  or  bearings 
turned  on  each  end  which  enter  into  the  holes  or  eyes  of  the  bolts. 
By  this  means  the  clamp  bar  may  turn  in  its  bearings  sufficiently 
to  have  its  flat  side  set  fairly  on  the  inclined  surface  of  the  taper. 


LATHE  WORK  259 

In  driving  bolts  which  are  to  be  threaded  and  in  which  the 
marks  of  the  center  hole  in  the  top  of  the  head  are  not  objectionable, 
a  "bolt  dog"  is  used.  This  is  simply  an  offset  plate  fastened  to 
the  face-plate  by  a  single  bolt  and  its  free  end  slotted  so  as  to  em- 
brace the  head  of  the  bolt.  This  device  is  not  much  used  at  the 
present  time  as  bolts  and  cap  screws  are  usually  made  from  a  bar 
in  the  turret  lathe  at  much  less  cost  than  is  possible  to  produce 
them  in  an  engine  lathe. 

Lathe  work  that  is  not  held  suspended  between  centers  must 
be  held  by  one  of  the  following  methods,  namely :  bolted  or  clamped 
to  the  face-plate ;  held  entirely  in  a  chuck ;  one  end  held  in  a  chuck 
and  the  other  in  a  center  rest;  or  secured  to  the  carriage,  or  some 
part  of  it,  as  in  boring  jobs.  One  exception  is  made  to  these  state- 
ments. This  is  that  work  may  be  held  against  the  head  spindle 
center  by  any  convenient  means,  and  the  other  end  supported  in 
a  center  rest.  This  is  usually  only  resorted  to  for  such  work  as 
boring  and  reaming  and,  with  the  exception  of  the  advantage  de- 
rived from  accurate  centering  by  means  of  the  head  spindle  center, 
is  not  a  very  advisable  method  of  running  work  in  a  lathe,  par- 
ticularly when  a  chuck  with  truly  concentric  jaws  is  at  hand. 

What  is  ordinarily  called  center  rest  work  is  all  kinds  in  which 
one  end  is  supported  in  a  center  rest.  Of  course  this  does  not  in- 
clude work  held  on  centers  and  supported  in  the  center  or  at  any 
intermediate  point  by  a  center  rest.  In  this  case  many  machinists 
call  it  a  "  steady  rest,"  rather  than  a  center  rest,  and  this  function 
may  be  readily  performed  by  a  back  rest  or  what  is  called  by  some 
manufacturers  a  steady  rest,  which  has  the  three  jaws  of  the  center 
rest,  although  they  are  not  placed  equidistant  around  the  circle 
and  the  supporting  casting  is  left  open  in  front  instead  of  being 
provided  with  a  hinged  top  segment. 

Chuck  work  and  face-plate  work  is  very  closely  allied,  and  in 
fact  very  many  face-plate  jobs  can  readily  be  done  in  a  chuck,  and 
nearly  all  chuck  jobs  can  be  done  if  fixed  to  the  face-plate  in  the 
usual  manner.  It  is  altogether  probable  that  the  first  chuck  made 
was  simply  a  face-plate  provided  with  jaws  temporarily  attached, 
and  it  is  more  than  likely  that  these  "jaws"  consisted  merely  of 
blocks  or  studs  fastened  to  the  face-plate  and  provided  with  set- 
screws  for  holding  the  work. 


260 


MODERN   LATHE  PRACTICE 


One  of  the  oldest  chuck  manufacturers  was  E.  Horton,  who 
established  the  business  in  1851.  One  of  the  Horton  three-jaw 
chucks  is  shown  in  Fig.  210. 

At  A  is  shown  a  face  view  of  the  finished  chuck.  It  consists  of 
a  front  and  a  back  plate  shown  respectively  at  D  and  B.  The 
jaws  are  moved  in  and  out  simultaneously,  by  means  of  the  geared 
steel  screws,  the  small  bevel  pinion  formed  on  them  engaging  the 
circular  steel  rack  C,  which  is  enclosed  in  a  deep  groove  or  recess 
in  the  back  plate  B,  as  shown.  At  D  is  shown  the  front  plate  with 
the  jaws  in  place,  with  the  projecting  portion  at  the  back  tapped 
to  receive  the  steel  screws,  which  are  shown  in  place.  The  front 


FIG.  210.  — The  Horton  Three-Jaw  Chuck. 

and  back  plates  fit  each  other  closely,  making  a  perfectly  tight 
casing  for  the  gearing  and  screws,  so  that  no  dirt,  chips,  etc.,  can 
possibly  get  into  them  and  clog  and  injure  the  gearing.  The  jaws 
are  forged  solid,  by  which  great  strength  is  secured  to  withstand  the 
strain  of  heavy  work. 

At  A,  Fig.  211,  is  shown  a  Sweetland  chuck,  which  in  a  general 
way  is  similar  to  the  Horton  chuck,  but  possesses  some  advantages, 
in  that  it  may  be  used  as  a  " universal"  chuck,  so  called,  in  which 
all  the  jaws  move  simultaneously  to  or  from  the  center,  or  it  may  be 
readily  changed  so  that  the  jaws  work  independently  of  each  other, 
thus  adapting  it  to  a  large  variety  of  irregular  and  eccentric  work. 


LATHE  WORK  261 

The  design  of  the  improvement  is  to  make  the  chuck  independ- 
ent as  well  as  universal,  thus  combining  two  chucks  in  one.  In 
the  recess  underneath  the  rack  are  the  cam  blocks,  beveled  to  cor- 
respond with  the  level  recess  in  the  rack.  The  cam  blocks  are  held 
in  place  by  the  convex  spring  washers,  which  allow  them  to  be 
moved  to  or  from  the  center  without  disturbing  the  nuts,  the  friction 
being  sufficient  to  hold  them  in  place.  When  moved  to  the  outer 
portion  of  the  rack  they  connect  the  gearing,  making  the  chuck 
universal,  and  when  moved  inward  they  disconnect  the  gearing, 
thus  making  each  screw  independent. 

The  advantage  of  making  each  screw  independent,  without  dis- 
connecting the  others  from  the  gearing,  is  a  feature  not  combined 
in  any  other  chuck,  and  is  an  improvment  fully  appreciated  by  the 


FIG.  211.  —  Sweetland  Four- Jaw  Chuck,  and  Cushman  Face-Plate  Jaws. 

mechanic  when  adjusting  the  jaws  for  eccentric,  concentric,  or  uni- 
versal work.  For  instance,  the  chuck  having  been  used  independ- 
ent, the  workman  wishes  to  change  to  universal,  the  jaws  are  moved 
inward  until  the  outer  end  is  true  with  the  line  on  face  of  chuck; 
now  each  screw  can  be  engaged  with  the  rack  separately  by  sliding 
the  cam  block  outward.  If  one  jaw  is  found  to  be  out  of  true  it 
can  be  disconnected  and  reset,  leaving  the  others  in  mesh  undis- 
turbed. 

This  chuck  has  a  large  hole  in  center,  and  will  allow  a  drill  or 
reamer  to  pass  through  work  without  injury  to  face  of  chuck. 

The  jaws,  rack,  and  pinion  screws  are  made  from  forged  steel, 
and  all  wearing  parts  properly  tempered. 

The  "bites"  on  the  jaws  are  ground  true  after  being  hardened 
and  tested  thoroughly  before  coming  out  of  the  grinding  machine. 


262  MODERN   LATHE  PRACTICE 

At  Fig.  211  are  shown  the  face-plate  jaws  heretofore  referred  to, 
and  which,  when  attached  to  a  face-plate,  make  a  very  serviceable 
and  practical  substitute  for  a  chuck,  and  advisable  to  have  from 
questions  of  economy,  even  on  lathes  as  small  as  30-inch  swing, 
while  on  lathes  above  40-inch  swing  they  are  all  the  more  useful, 
and  on  50-inch  swing  and  larger  are  almost  indispensable,  as  the 
largest  chucks  usually  made  are  42-inch  and  these  are  very  heavy 
and  very  expensive,  while  a  set  of  four  jaws  for  the  face-plate  may 
be  had  at  a  comparatively  nominal  cost. 

Figure  212  shows  three  forms  of  chucks.     At  A  is  a  Horton 


FIG.  212.  —  Horton  and  Cushman  Chucks. 

chuck  with  four  jaws.  It  is  built  on  the  same  plan  as  the  three-jaw 
chuck  shown  in  Fig.  210. 

At  B  is  shown  a  Horton  chuck  with  two  jaws,  which  is  very 
useful  for  certain  classes  of  work,  and  better  adapted  than  those  of 
three  or  four  jaws. 

Not  only  the  Horton  chucks  but  also  those  of  other  makers  are 
built  with  two,  three,  four  or  six  jaws,  as  the  nature  of  the  work 
may  demand. 

At  C  is  shown  a  Cushman  two-jaw  chuck,  with  provision  for 
slip,  or  "false  jaws."  By  this  construction  special  jaws  may  be 
made  with  faces  of  such  contour  as  to  fit  the  irregular  form  of  the 
pieces  to  be  machined.  This  form  of  chuck  is  used  for  the  machin- 
ing of  valve  bodies  and  similar  work,  and  is  sometimes  fitted  with 
various  indexing  devices  by  means  of  which  the  piece  may  be  turned 
from  side  to  side  and  held  while  various  operations  are  performed. 

Special  chucks  are  made  of  various  forms  and  with  a  varying 
number  of  jaws,  of  a  variety  of  different  shapes,  all  of  which  are 
too  numerous  to  illustrate  or  describe  here. 

In  chucking  cylindrical  work  with  a  universal  chuck  of  three 


LATHE   WORK  263 

jaws  the  work  is  correctly  centered  by  the  chuck  jaws,  provided 
there  are  no  uneven  places  on  the  work,  which  by  coming  under 
either  of  the  jaws  tend  to  throw  it  out  of  true.  Such  work  is  usually 
that  of  boring,  reaming,  or  facing,  and  similar  work  on  the  face  or 
inside  of  the  casting  or  forging,  and  such  part  of  the  outside  as 
extends  beyond  the  chuck  jaws. 

It  should  not  be  forgotten  that  while  we  usually  grip  work  upon 
the  outside,  the  chuck  jaws  work  equally  well  by  bearing  against 
the  inside  of  the  work;  for  instance,  the  inside  of  the  rim  of  a  gear 
that  is  to  be  faced,  bored,  and  reamed. 

When  round  rods  or  bars  are  to  be  machined  or  pieces  cut  from 
them,  whether  to  be  partly  machined  or  not,  a  drill  chuck,  so  called, 
is  used.  This  is  a  two-jaw  chuck,  the  jaws  being  of  a  variety  of 
forms,  from  the  shape  shown  in  Fig.  212  to  V-shaped  jaws  with 
interlocking  teeth,  the  design  of  all  of  them  being  to  hold  the  bar 
or  drill  firmly,  with  as  little  force  applied  to  the  right  and  left  screw 
that  operates  them  as  possible. 

Work  may  be  such  that  one  end  is  held  in  the  chuck  and  the 
other  supported  by  the  tail-stock  center,  or  by  a  center  rest  whose 
jaws  furnish  a  three-point  bearing  for  the  cylindrical  surface  of  the 
work.  While  the  method  of  supporting  the  work  by  the  tail-stock 
center  is  used  for  work  that  is  to  be  turned,  the  second  method,  that 
of  supporting  the  work  in  a  center  rest,  is  better  adapted  for  drilling 
and  reaming  operations.  These  operations  may  be  wholly  done 
with  the  drill  and  reamer,  or  by  the  use  of  an  inside  boring  tool 
held  in  the  tool-post  of  the  compound  rest. 

It  is  a  common  job  to  have  to  face  up  the  flanges  on  the  ends  of 
pipe  of  various  sizes.  Sometimes  these  pipes  are  of  wrought  iron  or 
steel  with  the  flanges  screwed  on.  Sometimes  they  are  cast  upon 
cast  iron  pipe.  The  ordinary  method  is  to  hold  one  end  in  a  chuck 
and  the  other  end  on  a  "pipe  center,"  of  one  form  or  another.  One 
form  of  these  centers  is  called  a  "  spider  center,"  and  often  con- 
sists of  any  convenient  casting,  circular  in  form,  that  comes  handy. 
With  several  set-screws  tapped  radially  into  its  edges  and  adapted 
to  be  backed  out  against  the  inside  of  the  pipe  and  firmly  held, 
while  a  drilled  and  countersunk  hole  in  the  center  affords  a  good 
bearing  for  the  lathe  center.  Mr.  Mortimer  Parker  suggests  some 
improved  forms  which  are  shown  in  Fig.  213,  in  which  A  shows  a 


264 


MODERN  LATHE   PRACTICE 


new  spider  center  which  is  quite  different  from  the  old  style  B  that 
requires,  as  shown,  a  block  of  wood  against  it  to  keep  it  from  shov- 
ing in  or  twisting  sideways  when  the  center  is  pressed  against  it, 
or  when  a  heavy  cut  is  started. 

This  improved  center  will  stand  a  heavier  cut  and  can  be  set 
quicker  than  the  other  style.  If  the  outside  is  turned  true  with 
the  hole  the  job  can  be  set  very  readily.  C,  D,  and  E  show  end 
views  of  different  forms  of  this  center;  and  F,  G,  and  H  are  differ- 
ent sizes  with  bronze  bushings  in  the  interior. 

At  I  is  illustrated  the  manner  in  which  a  common  cone  center 


FIG.  213.  —  Pipe  Centers  and  Spiders. 

can  be  turned  into  a  spider  center  by,  drilling  three  rows  of  holes 
and  putting  in  set-screws  and  jam-nuts,  only  one  set  of  screws  being 
needed,  as  they  can  be  used  in  either  series  of  holes. 

A  spider  center  allows  room  for  the  tool  to  clear  when  facing 
off  the  end  of  a  flange,  but  a  cone  center  does  not.  When  the  tool 
gets  down  to  the  center,  as  at  J,  it  leaves  a  shoulder  which  must 
be  turned  off  with  a  pointed  tool. 

K  is  a  center  with  a  cone  bearing  at  each  end  of  the  hole,  which 
keeps  free  from  play  even  if  it  does  wear.  Center  L  is  less  work  to 
make,  but  does  not  turn  around  when  a  heavy  cut  is  taken ;  hence  a 
ball-thrust  bearing  should  be  used  as  at  M  for  heavy  work. 


LATHE  WORK  265 

Center  N  works  well  in  a  heavy  cut  and  is  easily  made.  Center 
0  is  less  work  to  make  than  any  of  the  others  and  also  works  well 
with  heavy  work. 

In  facing  up  pipe  flanges  it  is  sometimes  the  practice  to  hold  one 
end  in  the  chuck  and  support  the  other  end  in  a  center  rest.  The 
disadvantage  of  this  method  is  that  the  roughness  of  the  out- 
side of  the  pipe  is  a  very  poor  bearing  for  the  center  rest  jaws 
and  poor  work  in  facing  is  likely  to  result,  while  the  same  pipe 
carried  on  a  pipe  center,  in  the  same  lathe,  will  be  a  creditable 


Lathe  arbors  are  an  important  adjunct  to  lathe  work.  They 
are  commonly  called  arbors  although  the  old  English  name  of 
mandrel  is  the  proper  word,  as  an  arbor  is  properly  a  carrier  for  a 
tool,  as  a  saw  arbor,  a  milling  machine  arbor,  etc.,  while  a  mandrel 
is  used  for  carrying  a  piece  of  work  to  be  turned. 

Mandrels  are  of  two  kinds,  solid  and  expanding.  The  solid 
mandrel  should  be  made  of  hard  machine  steel  or  a  cheap  grade  of 
cast  steel  capable  of  being  hardened. 

In  Figure  214  are  shown  two  forms  of  arbors.    That  at  A  is  the 


B 

FIG.  214.  —  Lathe  Mandrels  or  Arbors. 

common  form.  The  ends  are  turned  down  somewhat  smaller  than 
the  central  body,  and  on  one  side,  at  each  end,  is  a  flat  space  for  the 
set-screw  of  the  lathe  dog  to  rest  upon.  The  ends  are  slightly  re- 
cessed around  the  center  hole  so  that  it  will  not  be  bruised  if  the 
end  is  struck  with  a  hammer.  The  central  body  should  be  ground 
with  a  very  slight  taper.  The  entire  piece  should  be  hardened, 
not  simply  the  ends,  as  formerly.  A  J-inch  arbor  should  be  3  J  inches 
long  and  a  4-inch  arbor  18  inches,  all  intermediate  sizes  being  of  the 
same  proportion. 

At  B,  Fig.  214,  is  shown  an  expanding  arbor  or  mandrel.  This 
is  made  in  two  parts,  the  arbor  proper  and  an  outer  shell.  The 
inner  arbor  is  turned  and  ground  to  a  considerable  taper  and  the 
outer  shells  accurately  fitted  to  it.  It  is  then  split,  as  shown, 


266  MODERN   LATHE   PRACTICE 

by  from  eight  to  twelve  cuts,  alternately  beginning  at  opposite 
ends,  so  that  in  forcing  the  inner  arbor  in  on  the  taper  the  outer 
shell  is  expanded  in  very  nearly  a  circular  form,  at  least  near  enough 
for  all  practical  purposes.  At  the  end  of  each  cut  is  drilled  a  small 
hole  to  prevent  cracking. 

A  cheap  imitation  of  this  really  excellent  device  is  made  by 
splitting  the  outer  shell  all  the  way  through  at  one  point  only,  which 
will  do  as  a  makeshift  when  nothing  better  can  be  had. 

There  are  various  forms  of  expanding  arbors,  some  of  which 
have  considerable  merit  and  others  very  little.  The  one  illustrated 
above  will  probably  be  found  to  give  the  best  satisfaction. 

In  making  solid  arbors  it  should  be  remembered  that  they  must 
be  turned  considerably  over  size,  then  hardened,  which  will  change 
their  form  somewhat,  and  then  rough  ground  to  nearly  the  proper 
size.  They  should  then  be  laid  aside  for  some  time  to  give  the  steel 
an  opportunity  to  take  on  its  final  changes  and  attain  a  permanent 
condition  as  to  size,  straightness,  etc.,  before  it  receives  its  final 
finish  grinding,  which  should  diminish  its  diameter  very  slightly. 

The  drilling  in  the  ends  for  the  center  hole  and  the  countersink- 
ing should  be  carefully  done,  the  angles  of  the  sides  of  the  counter- 
sunk hole  being  exactly  60  degrees. 

Arbors  are  hardened  for  several  reasons,  principally  to  make 
them  accurately  cylindrical,  much  stiff er  and  more  rigid,  and  also 
less  liable  to  accidental  injury,  but  not  to  prevent  lathe  tools  from 
cutting  into  them  when  used  by  a  careless  workman. 

The  taper  on  an  arbor  is  usually  about  a  hundredth  of  an  inch 
per  foot  with  the  center  of  the  arbor  of  the  standard  diameter.  The 
fact  that  the  arbor  is  tapered  to  this  extent  makes  it  necessary  to  be 
careful  to  force  the  arbor  into  the  reamed  hole  from  the  same  side 
that  the  reamer  has  entered,  which  should  also  be  the  same  side 
first  entered  by  the  piece  that  is  to  fit  in  the  hole,  provided  it  is  to  be 
a  close  fit.  This  is  frequently  marked  on  the  drawing  and  it  should 
always  be  so  indicated  for  the  guidance  of  the  workman. 

Hardened  and  ground  mandrels  serve  the  very  excellent  pur- 
pose of  preserving  the  uniformity  of  sizes  of  holes,  since  if  the  holes 
are  not  truly  sized  the  pieces  will  either  drop  on  to  the  arbor  too 
loosely  or  fail  to  go  on  sufficiently  for  good  and  convenient  work. 
Again,  the  arbor  being  so  slightly  tapering,  the  workman  will 


LATHE  WORK 


267 


notice  even  a  small  difference  in  the  diameter  of  the  hole  by  the 
position  of  his  piece  on  the  arbor,  and  is  likely  to  report  the  defect 
in  the  work  in  this  respect. 

The  use  of  expanding  arbors  has  not  these  advantages  as  they 
are  ground  perfectly  straight.  But  they  are  to  be  preferred  for 
this  very  reason  when  running  fits  are  desired. 

Arbors  should  not  be  driven  into  reamed  holes  with  a  hammer. 
An  arbor  press  should  be  used  and  the  author 
knows  of  none  better  than  the  Greenard 
press,  which  is  made  in  various  sizes,  from 
the  small  one  to  fasten  to  the  tail  end  of 
the  lathe  bed  to  the  largest  sizes  which  have 
a  broad  floor  base.  One  of  the  former  is 
shown  in  Fig.  215.  By  the  use  of  these 
presses  there  is  no  shock  in  forcing  an  arbor 
into  the  work,  and  therefore  neither  the  ar- 
bor nor  the  work  is  injured.  In  addition 
to  this  advantage,  the  arbor  maintains  a 
perfect  alignment  with  the  hole  as  it  is 
forced  in,  and  therefore  there  is  no  unequal 
strain  or  distortion. 

The  rack  and  pinion  arrangement  of  this 
arbor  press  is  at  once  simple  and  effective, 
and  the  rotating  table  with  its  various  sized  recesses  in  the  edge 
furnishes  an  excellent  bed  for  supporting  the  work  as  the  arbor  is 
forced  into  it.  A  more  convenient  arrangement  could  scarcely 
be  imagined  for  this  work. 


FIG.  215  A.  —  Green- 
ard's  Arbor  Press. 


CHAPTER  XIV 

LATHE   WORK   CONTINUED 

Irregular  lathe  work.  Clamping  work  to  the  face-plate.  Danger  of  distort- 
ing the  work.  A  notable  instance  of  improper  holding  of  face-plate  work. 
The  turning  of  tapers.  Setting  over  the  tail-stock  center.  Calculating 
the  amount  of  taper.  Taper  attachments.  Graduations  on  taper  attach- 
ments. Disadvantages  of  taper  attachments.  Fitting  tapers  to  taper 
holes.  Taper-turning  lathes.  Turning  crank-shafts.  Counterbalancing 
the  work.  Angle  plate  for  holding  the  crank-shaft.  Forming  work. 
Forming  lathes.  Drilling  work  on  the  lathe.  Chuck  and  face-plate 
drilling.  Holding  work  on  the  carriage.  Boring  a  cylinder.  The 
author's  design  for  boring  large  cylinders.  Holding  work  by  an  angle- 
plate  on  the  face-plate.  Thread  cutting.  Calculations  for  change-gears. 
Reverse  gears.  Arrangement  of  the  change-gears.  Ratio  of  change- 
gears  equal  to  ratio  of  lead  screw  to  the  thread  to  be  cut.  Cutting  left- 
hand  threads.  Compound  gearing.  Calculating  compound  gears. 
Cutting  double  threads.  Triple  and  quadruple  threads.  Boring  bars. 
Varieties  of  boring  bars.  Driving  boring  bars.  Boring  large  and 
deep  holes.  The  author's  device.  The  drill,  boring  bar  and  cutters 
for  the  work.  Flat  cutters  for  boring  holes.  Boring  bar  heads  or  arms. 
Hollow  boring  bars.  Milling  work  on  a  lathe.  Milling  and  gear  cutting 
on  a  speed  lathe.  Grinding  in  a  lathe.  Cam  cutting  on  a  lathe.  Many 
uses  for  the  engine  lathe. 

THERE  is  so  much  irregular  work  constantly  done  on  the  lathe 
that  no  specific  description  of  it  can  be  given.  It  is  the  unknown 
quantity  that  the  machinist  has  to  deal  with  and  he  is  expected  to 
be  equal  to  the  occasion  and  so  fertile  of  resources  as  to  be  ready 
with  a  proper  method  for  doing  every  job  that  turns  up,  that  he 
will  not  be  obliged  to  hesitate  long  for  means  to  accomplish  the  end 
sought. 

Much  of  what  may  properly  be  called  irregular  work  will  be 
such  as  can  be  handled  on  the  face-plate  or  in  an  independent  jaw 
chuck.  Yet  these  appliances  for  holding  the  work  will  frequently 

268 


LATHE  WORK   (CONTINUED) 


269 


have  to  be  supplemented  by  the  tail-stock  center,  the  center  rest, 
and  the  follow  rest,  as  well  as  the  taper  attachment. 

In  clamping  work  on  the  face-plate  there  is  danger  of  springing 
the  work  as  it  is  fastened  down.  The  result  will  be  that  it  is  held 
in  a  distorted  position  while  being  machined,  and  upon  being  re- 
leased by  the  bolts  of  other  clamping  devices  it  will  spring  back  to 
its  original  position  and  so  show  distorted  machining.  For  this  rea- 
son much  care  should  be  exercised  to  see  that  it  rests  fairly  on  the 
face-plate  immediately  under  the  clamps  or  bolts  that  hold  it  down. 

The  same  idea  applies  to  rings  or  similar  shapes  when  held  in 
the  jaws  of  a  chuck  or  in  face-plate  jaws.  There  is  always  the  pos- 
sibility of  springing  them  out  of  shape  and  that  this  forcing  process 
will  show  in  distorted  work  when  the  piece  is  taken  out  of  the  lathe. 
The  author  once  saw  rings  of  cast  iron  two  inches  thick,  6  inches 
wide,  and  about  30  inches  inside  diameter,  pressed  out  of  shape 


FIG.  215  B.  —Turning  Tapers. 

by  the  face-plate  jaws  attached  to  a  60-inch  face-plate,  so  much 
that  several  of  them  were  spoiled,  and  the  expedient  of  strapping 
them  to  the  face-plate  had  to  be  resorted  to  in  order  to  produce 
work  as  true  as  the  job  called  for. 

Work  may  also  be  distorted  when  carried  in  a  steady  rest,  a  back 
rest  or  a  center  rest,  by  this  attachment  having  been  set  out  of  line, 
either  too  high,  too  low,  or  to  one  side.  Much  more  care  is  needed 
in  adjusting  these  attachments  than  they  sometimes  receive. 

The  turning  of  tapers  may  be  classed  as  irregular  turning  work. 
•  If  they  are  slight  the  tail-stock  center  may  be  set  over  sufficiently 
to  give  the  required  inclination,  particularly  if  the  work  is  long. 
When  the  taper  is  considerable,  it  will  not  be  proper  to  set  the  tail- 
stock  center  over  for  this  purpose  as  it  throws  the  head-stock  and 
tail-stock  centers  too  much  out  of  alignment  to  work  properly. 
This  is  shown  in  Fig.  215.  One  half  the  taper  shown,  on  this  length 


270  MODERN   LATHE   PRACTICE 

of  work  would  be  practical.  In  this  engraving  A  is  the  head  center 
and  B  the  tail  center. 

It  will  be  noticed,  however,  that  if  the  work  is  but  half  as  long 
and  the  tail-stock  center  located  at  C,  the  inclination  will  be  twice 
as  great  and  consequently  the  error  in  the  alignment  of  the  centers 
double  what  it  would  be  with  the  tail-stock  center  located  at  B, 
and  the  case  more  impractical  than  at  first. 

The  tail-stock  is  arranged  so  that  the  center  may  be  set  over  to 
the  rear  as  well  as  the  front,  so  that  the  small  end  of  the  taper  may 
be  toward  the  head-stock  when  such  a  position  is  more  convenient. 

In  setting  over  the  tail-stock  center  it  must  be  borne  in  mind 
that  the  difference  in  diameter  between  the  large  and  the  small  end 
will  be  twice  the  distance  which  the  center  is  moved  from  the  center 
line  of  the  lathe.  Therefore,  if  the  work  is  two  feet  long,  and  we  want 
a  taper  of  one  inch  in  two  feet,  or  half  inch  per  foot,  we  set  the  tail 
spindle  over  half  an  inch.  The  amount  set  over  at  the  tail-stock 
gives  double  that  taper  in  the  whole  length  of  the  work. 

Consequently,  if  we  divide  the  amount  of  taper  on  the  entire  length 
of  the  work  by  the  number  of  feet  in  length,  we  get  the  taper  per  foot. 
If  this  simple  rule  is  remembered  the  mistakes  that  often  occur  in 
turning  tapers  will  be  avoided. 

In  all  taper  turning,  however,  it  will  not  be  sufficiently  accurate 
to  measure  the  amount  of  tail-stock  set  over,  but  the  work  must 
be  carefully  calipered  as  the  turning  process  goes  on. 

When  the  taper  is  considerable,  it  is  better  to  do  the  work  in  a 
lathe  having  a  taper-turning  attachment.  Examples  of  this  de- 
vice will  be  found  in  the  chapter  on  lathe  attachments,  where  it 
will  be  seen  that  the  travel  of  the  compound  rest  in  a  transverse 
direction  is  governed  by  a  swiveling  bar  which  may  be  set  at  any 
desired  inclination  with  the  V's  of  the  lathe. 

While  there  are  usually  graduations  on  the  end  of  the  taper 
attachment  that  are  intended  as  a  guide  in  setting  the  swivel-bar  or 
guide,  they  are  frequently  misunderstood  and  consequently  useless. 
Usually  they  are  marked  for  so  much  taper  per  foot,  and  when  so 
designated  the  length  of  the  work  in  feet  must  be  considered,  if  the 
diameters  at  the  large  and  small  ends  are  given  on  the  drawing. 

If  the  taper  slide  or  guide-bar  is  graduated  in  degrees,  the  case 
is  nearly  hopeless  with  the  usual  machinist,  as  the  graduations  are 


LATHE   WORK   (CONTINUED)  271 

of  no  benefit  whatever  to  him,  as  his  drawing  will  very  seldom  be 
dimensioned  in  this  manner,  but  rather  the  extreme  diameters 
given,  or  the  taper  will  be  so  much  per  foot. 

The  use  of  the  taper  attachment  permits  a  much  wider  range  of 
tapers  to  be  turned  than  can  be  successfully  accomplished  by  means 
of  the  set-over  feature  of  the  tail-stock.  And  we  have  the  great 
additional  advantage  of  always  keeping  the  centers  in  line,  so  that 
accurate  work  can  be  done,  which  is  not  always  the  case  when  the 
tail-stock  is  set  over,  except  for  very  slight  tapers. 

One  of  the  drawbacks  to  the  use  of  taper  attachments  is  that 
a  certain  amount  of  back-lash  is  liable  to  exist  when  many  parts 
are  necessary  to  the  design  of  the  mechanism,  from  the  guide-bar 
or  swivel-bar  to  the  point  of  the  cutting-tool.  These  will  give  a 
certain  amount  of  difficulty  in  making  a  straight,  smooth  cut. 
Consequently,  the  gibs  should  be  set'  up  as  close  as  practicable,  all 
nuts  and  adjusting  screws  set  up  tight  and  as  much  vibration  and 
back-lash  eliminated  as  possible,  and  then  the  back-lash  be  taken 
up  by  hand  before  the  tool  begins  to  cut. 

In  all  taper  turning  it  is  necessary  that  the  point  of  the  tool  be 
set  at  exactly  the  height  of  the  points  of  the  centers,  otherwise  a 
true  taper  will  not  be  the  result  but  will  be  slightly  concave  rather 
than  in  a  straight  line. 

In  all  cases,  in  turning  tapers  to  fit  a  tapering  hole,  the  exact 
amount  of  taper  should  first  be  obtained  so  as  to  fit  the  tapering 
hole,  but  to  be  considerably  larger  than  its  final  size.  Then  the 
diameter  is  turned  correct,  the  calipering  being  usually  done  at  the 
small  end. 

Taper-turning  lathes  are  sometimes  made  in  which  the  head- 
stock  and  tail-stock  are  mounted  upon  a  separate  bed  which  is 
pivoted  at  the  center  so  that  it  practically  amounts  to  the  lathe 
swiveling  while  the  tool  carriage  runs  straight.  In  this  lathe  the 
centers  are,  of  course,  always  in  line,  the  setting  for  the  required 
result  is  quickly  done,  and  as  the  whole  mechanism  may  be  of  very 
rigid  construction,  the  work  done  on  it  is  very  accurate  as  well  as 
economical.  The  turning  of  crank-shafts  is  a  frequent  trouble  to 
the  inexperienced  man  who  has  this  work  to  do.  In  the  present 
case  it  is  assumed  that  the  crank-shaft  has  been  properly  "laid  off" 
with  a  surface  gage,  on  the  surface-plate  or  table,  and  the  centers 


272 


MODERN   LATHE  PRACTICE 


located,  drilled,  and  reamed,  and  the  shaft  proper  roughed  out  to 
nearly  its  finished  dimensions. 

The  operation  to  be  performed  is  to  turn  the  wrist-pin.  This  is 
shown  in  Fig.  216.  At  A  is  shown  the  usual  method  of  rigging  up 
for  the  job.  The  shaft  is  placed  in  V-blocks  on  the  surface  table 
and  the  wrist-pin  blocked  up  to  the  proper  height,  as  shown  by  the 
surface  gage,  so  that  there  will  be  stock  enough  left  on  all  sides  to 
finish  up  to  the  given  dimensions.  The  "offsets"  or  " throws," 
C,  C,  are  now  put  on  and  the  centers  accurately  located  by  the 

_£> 


1 

D 

L             _i 

1 

i 

1 

J: 

—  i 

—  i 

—  ' 

C 

rl 

^ 

FIG.  216.  —  Turning  Crank-Shafts. 

surface  gage  before  the  set-screws  are  screwed  up  tightly  to  hold 
them  in  place.  I 

The  centers  are  now  measured  all  around  with  the  surface  gage 
once  more,  to  make  sure  that  all  are  in  the  same  plane.  The  crank- 
shaft is  now  placed  in  the  lathe,  the  centers  in  the  offsets  being 
used  as  they  are  directly  in  line  with  the  wrist-pin  center.  A  tool 
long  enough  to  reach  down  between  the  arms  of  the  crank  must  be 
used.  It  should  be  made  with  a  very  narrow  point,  be  kept  very 


LATHE  WORK  (CONTINUED)  273 

sharp,  and  set  either  on  the  center  or  but  a  trifle  above  it.  The 
idea  is  to  avoid  as  much  as  possible  any  undue  strain  in  the  turning, 
as  the  work  will  not  be  very  rigid  and  the  cuts  taken  must  be  light. 
The  wrist-pin  being  turned  and  finished,  the  offset  pieces  C,  C, 
are  removed,  a  block  fitted  in  the  space  D,  between  the  arms  of  the 
crank,  and  it  is  placed  on  the  shaft  centers  and  finished  as  any  other 
shaft  would  be. 

One  of  the  precautions  that  should  be  taken  is  to  have  the  work 
properly  counterbalanced  by  adding  on  the  face-plate  the  proper 
weight,  opposite  the  crank  when  turning  the  shaft,  and  opposite  the 
shaft  when  turning  the  wrist-pin,  so  as  to  prevent  undue  strain 
and  vibration. 

Another  and  more  rigid  arrangement  is  shown  at  B,  in  Fig.  216, 
in  which,  in  place  of  an  offset  piece  at  the  face-plate  end,  the  bracket 
or  angle-plate  E  is  used.  This  is  bolted  to  the  face-plate  and  has 
a  cap  F  fitted  to  it  and  bolted  firmly,  with  the  joint  held  slightly 
apart  with  paper  or  thin  cardboard.  It  is  then  bored  out  the 
exact  diameter  of  the  end  of  the  crank-shaft,  which  is  firmly  gripped 
in  it  and  the  shaft  much  more  rigidly  held  than  in  the  former 
example.  The  offset  piece  C  is  used  at  the  tail-stock  center  the 
same  as  before. 

In  all  these  operations  great  care  should  be  used  to  lay  out  all 
the  centers  in  the  same  plane,  and  to  locate  the  offset  arms  in  the 
same  manner.  The  free  and  careful  use  of  the  surface  gage  will 
be  necessary  to  success. 

Forming  work  has  been  described  in  another  part  of  this  book, 
and  the  reader  interested  in  this  class  of  work  is  referred  to  the 
chapters  in  which  these  matters  are  considered.  The  particular 
points  to  be  observed  in  forming  work  are:  to  hold  the  work  very 
rigid;  to  have  a  very  rigid  cutting  or  tool  carriage;  to  have  a  tool 
with  a  very  sharp  and  carefully  "stoned-up"  cutting  edge;  to  use 
a  comparatively  slow  speed  and  a  very  fine  feed. 

When  these  conditions  are  obtained  the  forming  lathe  works 
easily,  accurately,  and  efficiently. 

The  tools  must  be  so  formed  that  by  continually  grinding  on  the 
top  the  form  and  contour  of  the  cutting  edge  is  not  changed. 

The  forming  lathe  may  have  an  automatic  feed  with  a  stop  which 
automatically  throws  out  the  feed  when  the  proper  diameter  is 


274  MODERN  LATHE  PRACTICE 

reached.  This  makes  the  lathe  semi-automatic,  in  that  it  need  only 
be  set  and  started,  and  no  further  attention  given  to  it  until  the 
cut  is  completed.  Thus  one  man  may  run  a  number  of  machines, 
and  the  relative  efficiency  of  each  will  be  reckoned,  not  so  much 
in  the  large  number  of  pieces  turned  out,  as  in  the  small  cost  for 
labor,  which  is  usually  the  most  expensive  item  on  this  and  similar 
classes  of  work. 

This  is  seen  very  readily  in  the  automatic  screw  machine,  which 
turns  out  much  of  its  work  much  more  slowly  than  the  turret  lathe. 
But  the  turret  lathe  requires  the  constant  attendance  of  a  skilled 
operator,  while  one  man  may  take  care  of  from  four  to  ten  automa- 
tic screw  machines. 

In  many  respects  the  engine  lathe  may  be  made  to  take  the 
place  of  the  upright  drill,  although  this  class  of  work  is  now  usually 
done  in  the  upright  drill,  the  radial  drill,  or  the  boring  machine. 
However,  there  are  shops  which  do  not  possess  all  these  facilities 
and  still  have  many  jobs  that  may  be  properly  done  in  the  lathe. 

To  the  ordinary  jobs  of  chucking  and  reaming  it  will  not  be 
necessary  to  refer.  The  same  may  be  said  of  ordinary  drilling 
such  as  may  be  done  by  holding  the  work  in  the  chuck  and  using 
either  a  flat  drill  with  a  center  hole  in  its  rear  end  for  the  tail-stock 
center,  and  the  drill  held  from  turning  by  a  wrench,  or  similar 
contrivance. 

Drills  may  be  held  in  the  tail-stock  spindle,  in  place  of  the  tail 
center,  if  the  taper  hole  is  standard  as  it  should  be,  or  when  the 
drill  shank  is  too  small  a  collet  may  be  used.  In  this  way  many 
jobs  of  chuck  or  face-plate  drilling  may  be  done.  When  the  work 
is  such  that  it  is  necessary  to  revolve  the  drill  instead  of  the  work, 
the  drill  may  be  transferred  to  the  head  spindle  and  the  work  held 
by  bolting  or  strapping  it  to  the  carriage,  the  compound  rest  having 
been  removed  for  that  purpose. 

Another  method  is  to  strap  to  the  carriage  an  angle  plate,  jig, 
or  other  fixture  suitable  for  holding  the  work  to  be  drilled. 

There  is  a  wide  range  of  possibilities  in  this  class  of  work  and  the 
ingenious  machinist  is  generally  very  resourceful  in  this  direction. 
The  following  is  a  case  in  point; 

It  is  often  necessary  to  bore  a  hole  so  large  that  it  is  not  con- 
venient to  do  it  in  the  ordinary  way,  by  bolting  to  the  face-plate, 


LATHE  WORK  (CONTINUED) 


275 


and  if  the  casting  has  no  hole  through,  or  one  so  small  as  to  require 
a  boring  bar  too  small  in  diameter  to  get  a  steady  rest  cut,  it  is 
almost  impossible  of  accomplishment  on  the  boring  machine.  The 
casting  shown,  marked  C  in  Fig.  217,  is  of  such  a  nature.  The  pri- 
mary factor  in  the  boring  of  these  cylinders  is  the  making  of  the 
bracket  A,  which  forms  a  solid  support  for  the  boring  bar  B.  The 
boring  bar  B  is  driven  in  the  usual  way,  or  rather  in  one  of  the  usual 
ways.  It  will  be  noticed  that  the  taper  shank  is  held  from  turning 
by  being  screwed  into  the  spindle  of  the  lathe  head-stock,  and  that 
it  has  a  conical  bearing  at  the  outer  end  in  the  bracket  A.  The 
bearing  is  thus  adjustable  to  take  up  "back-lash"  by  sliding  the 
bracket  A  to  the  right  along  the  lathe  bed,  which  in  this  case  is  of 


^    D  Carriage  ^ 

-^pron^i^"      ^§^J~~} 

Lathe  Bed  I 


FIG.  217.  —  Cylinder  Boring  in  the  Lathe. 

the  ordinary  English  pattern,  with  a  flat  bed.  Of  course,  by  mak- 
ing the  bottom  of  the  bracket  to  suit  the  raised  V's,  the  attachment 
is  capable  of  being  made  to  suit  the  American  style  of  bed. 

The  cylinder  C  is  bolted  upon  a  slotted  plate  attached  to  the 
carriage  D,  upon  parallels.  In  planing  the  base  of  the  castings, 
care  was  taken  to  make  them  in  all  cases  of  equal  distance  from  the 
face  of  the  base  to  the  center  of  the  casting  —  not  to  the  core,  as 
this  was  liable  to  be  slightly  out  of  true. 

Three  cutter  heads,  two  roughing  and  one  finishing,  were  made 
like  the  one  shown  at  F,  at  the  right,  in  Fig.  217.  All  had  four 
cutters  slanting  to  the  left  at  the  inner  end,  in  order  to  bring  the 
cutting  edges  outside,  or  near  the  end  of  the  block. 

At  the  right  of  Fig.  217  is  shown  one  of  the  blocks  in  detail. 


276  MODERN   LATHE  PRACTICE 

E  is  turned  to  the  angle  at  which  the  cutters  were  required  to  be 
fitted  at  the  point  G,  and  a  clamping  ring  F,  turned  to  fit,  was 
afterwards  clamped  on  by  means  of  four  filister  head  screws.  Four 
holes,  as  at  J,  in  the  small  view  at  the  right,  were  drilled  in  line  with 
the  joint  to  fit  the  cutters.  After  drilling,  a  small  amount  was 
turned  off  the  inner  face  of  the  clamping  ring  F  in  order  that  the 
tools  would  be  clamped  when  the  screws  were  tightened.  This 
ring  when  tightened  up  was  found  to  be  sufficient  to  prevent  the 
cutters  slipping  in. 

To  insure  the  cutters  all  having  an  equal  cut,  the  cutting  edges 
were  ground  and  also  backed  off  by  means  of  a  cutter  bar,  mounted 
on  the  slide-rest  and  driven  from  overhead.  The  finishing  cutter 
finished  from  six  to  a  dozen  holes  at  one  grinding  and  it  was  then 
a  simple  matter  to  set  them  out  a  little  and  regrind.  It  was  found 
to  be  advisable  to  take  out  and  grind  the  roughing  cutters  separately 
on  an  emery  wheel,  as  working  in  the  sand  they  wore  rapidly. 
Sometimes  one  broke  in  cutting  out  a  projecting  lump  of  metal  and 
they  wore  generally  unevenly. 

The  hole  H,  Fig.  217,  was  bored  out  (from  a  cored  hole)  by  two 
cutters,  as  shown  (roughing  and  finishing),  fluted  similarly  to  rose 
bits  or  reamers.  The  roughing  cutter  was  passed  through  at  the 
same  time  as  one  of  the  roughing  cuts  in  the  large  hole;  the  finish- 
ing cut,  however,  was  taken  separately  to  avoid  disturbing  the 
large  finishing  cut.  The  carriage  was  fed  up  mechanically  by  means 
of  the  rod  feed. 

The  device  for  doing  this  job,  when  once  made,  proved  to  be 
useful  on  other  jobs  as  well. 

The  author  once  designed  and  built  a  lathe  for  doing  a  similar 
job  to  the  one  here  described  and  illustrated,  but  on  a  much  larger 
scale.  In  this  case  it  was  required  to  very  rapidly  bore  and  finish 
large  cast  iron  cylinders  about  four  feet  in  diameter.  As  there  was 
ample  power  to  do  the  work,  and  sufficient  length  of  bed  was  allow- 
able to  bore  a  number  of  these  cylinders  at  a  time,  and  as  they  were 
quite  short  in  proportion  to  their  diameter,  the  lathe  was  arranged 
to  bore  two  cylinders  at  once,  with  three  tools  for  each  cylinder, 
namely,  a  roughing  tool,  a  sizing  tool,  and  a  finishing  tool.  Each 
of  these  consisted  of  a  cross  bar  attached  to  a  boring  bar,  and  carry- 
ing a  cutting  tool  on  each  end. 


LATHE  WORK  (CONTINUED)  277 

By  this  arrangement  there  were  twelve  cutting  tools  in  action 
most  of  the  time,  and  as  two  cylinders  were  bored  during  the  time 
of  the  travel  of  the  tool  across  one,  the  result  was  that  of  doubling 
the  capacity  of  the  former  machine  which  did  this  work. 

Another  method  by  which  boring  work  may  be  done  is  to  at- 
tach it  to  the  face-plate  of  a  lathe  by  the  use  of  an  angle-plate,  by 
which  means  various  shaped  pieces  having  a  finished  surface  at 
right  angles  to  the  axis  of  boring  may  be  conveniently  held.  El- 
bows are  well  handled  by  this  device  and  many  similar  jobs  will 
readily  suggest  themselves  to  the  machinist.  And  not  only  boring, 
but  many  jobs  of  turning  on  such  shaped  pieces  may  be  conveniently 
handled  by  the  use  of  the  angle-plate  attached  to  the  face-plate 
of  a  lathe. 

Thread  cutting  in  a  modern  lathe  provided  with  a  quick  change 
gear  device  for  cutting  any  number  of  threads  per  inch,  by  shifting 
one  or  more  levers,  is  a  comparatively  simple  matter.  With  a  lathe 
equipped  with  removable  change-gears  for  accomplishing  the  same 
purpose  it  is  much  more  complicated,  and  its  principles  frequently 
misunderstood.  Therefore  a  clear  understanding  of  these  prin- 
ciples is  necessary  to  any  one  who  aspires  to  become  an  intelligent 
machinist. 

The  spindle  or  head  shaft  of  the  lathe  runs  at  the  same  speed 
as  the  main  spindle;  therefore  it  takes  its  place  in  all  calculations 
for  thread  cutting.  Upon  this  spindle  the  first  change-gear  is 
placed.  The  lead  screw  carries  the  second  change-gear.  ,  The  ratio 
of  these  two  gears  determines  the  ratio  of  the  number  of  revolu- 
tions of  the  main  spindle  to  those  of  the  lead  screw.  The  change- 
gear  placed  between  this  first  and  second  change-gear  is  an  idler 
gear,  since  it  runs  loosely  on  a  stud  and  serves  only  to  communicate 
motion,  but  does  not  in  any  way  change  or  modify  the  ratio. 

The  reverse  gears  within  the  head  are  used  only  for  reversing 
the  motion  of  the  head  shaft,  and  are  also  idler  gears,  not  affecting 
the  ratio. 

The  arrangement  is  shown  in  Fig.  218,  in  which  a  is  the  head 
shaft  or  spindle;  o  is  the  lead  screw,  and  c  the  adjustable  stud  in 
the  adjustable  stud-plate,  segment,  quadrant,  or  sweep,  as  it  is 
variously  termed,  marked  d.  A  is  the  first  change-gear ;  B  the  second 
change-gear,  and  C  the  idler  gear.  As  shown,  the  two  gears  A  and 


278 


MODERN  LATHE  PRACTICE 


B  are  of  equal  diameter  and  number  of  teeth,  consequently  the 
lead  screw  revolves  at  the  same  rate  of  speed  as  does  the  main 
spindle.  It  follows,  therefore,  that  if  the  lead  screw  is  cut  with 
four  threads  per  inch  the  lathe  carriage  will  move  a  quarter  of  an 

inch  with  each  revolution,   and  the 
lathe  will  cut  four  threads  per  inch. 

If  the  change-gear  A  is  only  one 
half  the  diameter  of  the  change-gear  B, 
the  lead  screw  will  revolve  only  one 
half  as  fast  as  the  main  spindle,  and 
the  lathe  will  cut  eight  threads  per 
inch;  while  if  the  change-gear  B  is  one 
half  the  diameter  of  the  change-gear  A, 
the  lead  screw  will  cut  two  threads  per 
inch. 

Therefore,  whatever  is  the  ratio  of 
f  1  the  two  change-gears,  A  and   B,  to 


accordingly,  and  produce  a  thread  of 
like  ratio  to  the  number  of  threads  per  inch  with  which  the  lead 
screw  is  cut.  Otherwise,  the  ratio  of  the  change-gears  A  and  B 
equals  the  ratio  of  the  thread  of  the  lead  screw  to  the  thread  to 
be  cut. 

To  cut  any  desired  number  of  threads  per  inch  it  is  first 
necessary  to  find  the  ratio  which  the  desired  number  of  threads 
bears  to  the  number  of  threads  on  the  lead  screw;  then  to  select 
such  change-gears  as  bear  this  ratio  to  each  other,  remembering 
that  if  the  desired  thread  is  of  a  coarser  pitch  than  that  of  the 
lead  screw,  the  change-gear  A  must  be  the  larger,  and  if  it  be  a 
finer  thread  than  that  of  the  lead  screw,  the  change-gear  B  must  be 
the  larger. 

The  gears  will  revolve  in  direction  of  the  arrows,  by  which  it  is 
seen  that  the  lead  screw  revolves  in  the  same  direction  as  the  change- 
gear  A  on  the  head  shaft  a,  and  consequently  as  the  main  spindle 
of  the  lathe.  This  arrangement,  with  a  right-hand  thread  (as 
usual),  on  the  lead  screw  6,  will  cut  right-hand  threads. 

When  it  is  desired  to  cut  left-hand  threads  the  motion  of  the 
lead  screw  must  be  reversed.  This  is  done  by  the  addition  of  the 


LATHE   WORK   (CONTINUED) 


279 


idle  gear  E  on  a  second  stud  e,  in  the  stud-plate  d,  as  shown  in  Fig. 
219. 

When  the  proper  ratio  cannot  be  obtained  by  the  use  of  the 
change-gears  at  hand,  or  when  the 
gears  of  the  desired  numbers  of  teeth 
would  be  too  small  to  properly  con- 
nect, or  too  large  to  be  put  in  place, 
recourse  must  be  had  to  what  is 
termed  compound  gearing.  Refer- 
ring to  Fig.  221,  and  the  series  of 
change-gears  A,  suppose  that  it  is  de- 
sired to  use  compound  gears,  making 
the  ratio  4  to  1.  A  36- tooth  gear  is 
placed  on  the  head-shaft  and  a  72- 
tooth  gear  on  the  lead  screw.  On  the 
idler  stud  we  place  two  gears,  a  48 
and  24,  fixed  to  each  other  by  placing 
them  on  a  splined  compounding  sleeve 
which  runs  loosely  on  the  stud.  The  36-gear  is  engaged  with  the 
48,  and  the  24  with  the  72,.  as  shown  in  elevation  at  A,  Fig.  220, 
and  more  clearly  seen  at  A,  in  the  diagram,  Fig.  221. 

The  result  of  this  combination  is  this:  If  the  36-gear  engaged 
the  72,  the  ratio  would  be  2;  and  if  the  24-gear  engaged  the  48, 


J 


FIG.  219.  —  Change-Gears  for 
Cutting  Left-Hand  Threads. 


FIG.  220. 


Compound  Change-Gears  for  Right 
and  Left-Hand  Threads. 


the  ratio  would  be  2.  These  ratios  multiplied  would  be  4.  As  they 
are  engaged  we  have  36  to  48,  which  is  a  ratio  of  1  J,  and  24  to  72 
is  a  ratio  of  3,  which  multiplied  by  1 J  produces  4. 

The  effect,  then,  of  introducing  the  24  and  48  gears  instead  of  a 


280  MODERN  LATHE  PRACTICE 

single  idle  gear  is  to  double  the  ratio  existing  between  the  gear  on 
the  head-shaft  and  the  one  on  the  lead  screw.  The  combination 
as  shown  would  cut  16  threads  per  inch  on  a  lathe  having  a  lead 
screw  cut  with  four  threads  per  inch.  (Usually  lathes  will  cut 
this  number  of  threads  without  compounding.  The  gears  here 
shown  and  described  are  given  as  a  simple  example.) 

At  B,  in  Figs.  220  and  221,  the  order  of  gears  is  reversed,  the 


Spindle  f~|  El  O  Spindle 


stud  I  f  mmu  stud 


t-ead  Screw  F     IF=IU  f?   ii=in  read  Screw 


A 

FIG.  221.  —  Edge  View  of  Compound 
Change-Gears . 

72-gear  is  placed  on  the  head  shaft  and  the  36-gear  on  .the  lead 
screw.  The  effect  now  is,  instead  of  multiplying  the  pitch  of  the 
lead  screw  by  4  (4  X  4  =  16  threads  per  inch  on  the  work  cut),  the 
number  of  threads  of  the  lead  screw  is  divided  by  4  (4-r-  4  =  1), 
thus  producing  in  the  work  a  screw  of  one  thread  per  inch,  or  one- 
inch  pitch. 

By  a  thorough  and  correct  understanding  of  these  principles 
there  should  be  no  difficulty  in  setting  up  a  lathe  for  any  desired 
number  of  threads  per  inch.  It  is  usual  to  have  compounding 
gears  of  a  ratio  of  2  to  1,  as  24  and  48,  36  and  72,  and  so  on.  But 
it  may  be  necessary  to  use  other  ratios  as  H  to  1,  say  48  and  72, 
24  and  36,  etc.  Or  to  make  the  ratio  3  to  1,  as  24  and  72,  36  and 
108. 

It  is  always  advisable  to  use  as  large  change-gears  as  possible, 
as  the  motion  of  the  lead  screw  is  more  regular  and  steady,  and  the 
strain  on  the  gear  teeth  is  less,  consequently  better  work  can  be 
done.  This  should  be  practised  even  if  compound  gears  have  to 
be  used  more  frequently. 


LATHE  WORK  (CONTINUED)  281 

In  cutting  double  threads  the  change-gears  are  set  for  double 
the  pitch,  that  is,  one  half  the  number  of  threads  which  the  finished 
thread  is  to  be.  Then  proceed  to  cut  one  of  the  threads,  leaving 
the  proper  blank  space  between  the  convolutions  for  putting  in  the 
second  thread.  To  locate  this  properly  a  tooth  in  the  stud  gear 
may  be  marked,  and  also  mark  the  space  in  the  intermediate  gear 
into  which  this  marked  tooth  has  meshed.  Now  lower  the  inter- 
mediate gear  out  of  the  mesh,  by  unscrewing  the  clamp  bolt  of  the 
stud-plate  for  the  purpose,  and  turn  the  spindle  exactly  one  half  a 
revolution,  that  is,  until  one  half  the  whole  number  of  teeth  have 
passed  the  marked  space  in  the  intermediate  gear,  and  the  marked 
tooth  is  exactly  opposite  its  former  position.  Raise  the  stud-plate, 
putting  the  two  gears  properly  in  mesh  with  each  other,  and  go  on 
with  the  cutting  of  the  second  thread.  This  is  assuming,  of  course, 
that  the  stud  gear  has  an  even  number  of  teeth  and  that  the  ratio 
between  the  lathe  spindle  and  the  head  shaft  or  gear  spindle  is  1 
to  1,  both  conditions  being  the  usual  ones. 

When  this  ratio  is  different,  it  is  readily  understood  that  the 
spindle  must  be  rotated  a  proportional  amount  which  is  governed 
by  this  ratio. 

Another  method  of  accomplishing  the  same  result  is  to  have 
two  dog-slots  in  the  small  face-plate  exactly  opposite  each  other, 
and  after  one  of  the  double  threads  is  finished,  to  shift  the  tail  of 
the  dog  into  the  other  slot. 

Triple  and  quadruple  threads  are  cut  in  a  similar  manner,  but 
all  the  details  of  the  work  are  much  more  complicated  and  diffi- 
cult, both  in  making  the  proper  calculations  to  insure  the  exact 
thickness  or  pitch  of  the  threads,  and  in  grinding  and  setting  the 
tool  so  as  to  get  the  correct  cutting  angles  and  clearance. 

Boring  bars  may  be  used  in  various  ways.  They  may  be  sup- 
ported on  both  centers  and  the  work  they  are  to  bore  strapped  to 
the  carriage.  They  may  have  one  end  fitted  to  the  taper  hole  in 
the  head  spindle  and  the  other  end  carried  by  the  tail-stock  center 
and  the  work  held  as  before.  Or,  the  boring  bar  may  similarly  be 
held  in  the  tail-stock  spindle  and  the  opposite  end  supported  in  a 
bushing,  in  the  center  hole  of  the  main  spindle,  while  the  work  may 
be  carried  in  one  of  two  ways.  That  is,  it  may  be  strapped  to  the 
face-plate,  or  held  in  a  chuck;  or;  if  comparatively  long,  cylindrical 


282 


MODERN   LATHE   PRACTICE 


work,  it  may  have  one  end  held  in  a  chuck  and  the  other  supported 
by  a  center  rest. 

The  author  once  had  a  job  of  this  kind  to  do  and  it  was  accom- 
plished successfully  by  the  arrangement  described  and  illustrated 
as  follows: 

Given  the  task  of  boring  a  5J-inch  hole  endwise  through  a  hard 
steel  spindle  7J  inches  in  diameter  and  5  feet  long,  with  a  large  and 
powerful  boring  lathe,  such  as  is  used  on  gun  work,  and  the  work 
would  be  comparatively  easy  and  rapid.  Having  only  the  equip- 
ment of  an  ordinary  machine  shop,  the  case  becomes  more  serious. 
In  the  regular  course  of  business  such  a  job  was  required  to  be  done, 


FIG.  222.  —  Boring  Bar  for  a  Long  Hole. 


and  the  work  was  performed  perfectly  and  expeditiously,  as  will 
be  described. 

Fortunately,  a  boring  lathe  was  at  hand,  fitted  with  a  chuck  and 
provided  with  a  sliding  carriage,  operated  by  an  automatic  feed 
and  designed  to  bore  a  2J-inch  hole,  25  inches  deep.  One  end  of 
the  spindle  to  be  bored  was  fixed  in  the  chuck  and  the  other  run 
in  the  jaws  of  a  center  rest,  as  shown  at  d,  Fig.  222. 

An  expert  blacksmith  forged  a  twist  drill  2  inches  in  diameter 
with  a  twist  of  31  inches  in  length,  which  was  turned  up  and  finished, 
and  with  this  a  hole  was  bored  a  little  over  30  inches  deep.  A  soft 
brass  tube  of  about  iVinch  bore,  carried  oil  under  pressure  to  the 
point  of  the  drill  and  on  its  return  brought  out  the  chips.  The 
spindle  was  then  reversed  and  the  hole  was  bored  from  the  opposite 
end  until  the  two  holes  met,  which  they  did  quite  exactly. 


LATHE  WORK  (CONTINUED)  283 

Now  came  the  work  of  enlarging  the  hole  from  2  inches  to  5J 
inches.  It  is  to  this  part  of  the  work  that  particular  attention  is 
called.  As  the  means  for  holding  the  drill  had  proven  very  rigid 
and  satisfactory,  a  boring  bar  was  constructed,  as  shown  in  the 
upper  illustration,  Fig.  222.  The  cutters  a  and  b  were  of  |-inch 
round  steel,  fitted  in  the  usual  way,  and  held  by  set-screws  c,  the 
bar  being  placed  in  a  lathe  and  its  ends  turned  off,  so  that  the  cutter 
a  would  measure  3|  inches,  and  b  5|  inches.  The  end  of  the  bar 
just  fitted  the  2-inch  hole  already  bored  in  the  spindle,  thereby 
furnishing  a  correct  and  certain  guide  and  support  near  the  cutters. 
The  cutting  ends  of  the  cutters  were  formed  as  shown  at  A,  Fig. 
222,  i.e.,  the  face  of  the  cutting  edges  being  inclined  5  degrees 
and  the  leading  edge  25  degrees,  making  the  angle  of  the  cutting 
edge  60  degrees,  which  proved  to  be  a  very  effective  construction, 
the  cutter  a  enlarging  the  hole  to  the  extent  of  taking  out  about 
half  of  the  stock  and  the  cutter  b  removing  the  remainder. 

The  spindle  was  then  reversed  and  the  operation  continued 
from  the  opposite  end  until  only  a  small  portion  of  the  2-inch  hole 
was  left  to  guide  the  boring  bar.  The  bar  was  then  withdrawn  and 
a  disk  e  fitted  to  it.  This  disk  was  5J  inches  in  diameter,  so  as  to 
just  fit  the  enlarged  hole  and  furnish  a  guide  for  completing  the 
enlargement  of  the  hole,  as  shown  in  the  lower  illustration. 

The  work  was  successfully  done,  a  true,  smooth  hole  bored, 
the  two  sections  of  which  coincided  perfectly.  It  will  be  noted 
that  in  this  job  the  hole  was  very  large  in  proportion  to  the  exterior 
diameter,  and  a  large  amount  of  stock  was  taken  out;  in  fact,  nearly 
350  pounds  of  hard  steel.  This  was  removed  at  the  rate  of  nearly 
30  pounds  per  hour. 

The  plan  will  doubtless  commend  itself  for  similar  work,  and 
where  there  is  even  a  greater  difference  between  the  directing  hole 
and  the  finished  bore  three  or  more  cutters  might  be  used  to  advan- 
tage. 

It  is  frequently  the  custom  to  fit  flat  cutters  in  elongated  mortises 
made  through  the  bar  instead  of  using  a  round  cutter  in  a  bored 
hole.  The  flat  cutters  will  be  proper  when  the  boring  bar  is  com- 
paratively small  in  diameter,  as  it  weakens  the  bar  less  than  a 
round  hole  of  sufficient  diameter  to  carry  a  cylindrical  cutter  of 
the  proper  strength.  Still  the  cylindrical  cutter  should  be  used 


284  MODERN   LATHE   PRACTICE 

whenever  possible,  both  for  rigidity  and  cutting  qualities  as  well  as 
economy. 

When  large  holes  are  to  be  bored  a  cross  arm  is  used  carrying 
a  cutter  on  each  end.  Sometimes  two  cutters  on  each  end  are 
used,  a  roughing  and  a  finishing  cutter. 

Sometimes  a  large  hollow  boring  bar  is  used,  carrying  a  cross- 
bar or  head  with  two  tools.  This  cross  bar  is  arranged  to  slide  on 
the  boring  bar  and  is  fed  forward  by  a  screw  passing  through  the 
center  of  the  bar  and  having  upon  it  a  nut  that  is  connected  with 
the  cross  head.  Such  an  arrangement  is  used  for  boring  engine 
cylinders.  These  boring  heads  are  often  driven  by  the  old  "  star- 
feed"  arrangement,  familiar  to  nearly  all  machinists. 

These  elaborate  devices  for  boring  are  usually  constructed  for 
special  boring  machines  and  may  hardly  be  considered  as  a  part  of 
the  equipment  of  an  engine  lathe. 

Milling  may  be  successfully  performed  on  a  lathe  by  strapping 
the  work  to  the  compound  rest,  to  the  carriage  or  to  a  suitable  fix- 
ture attached  to  either.  While  not  so  economical  or  so  rapid  as 
on  a  regular  milling  machine,  it  often  proves  very  advantageous 
when  a  milling  machine  is  not  at  hand  or  when  the  machines  of  the 
shop  are  crowded  with  work  so  as  not  to  be  available. 

Many  light  operations  of  milling  may  be  performed  on  a  speed 
lathe,  with  proper  fixtures  for  the  purpose,  particularly  when  the 
work  is  of  brass  or  similar  soft  metals.  In  these  cases  the  speed 
lathe  will  often  turn  out  as  much  work  as  the  plain  hand  milling 
machine. 

Gear  cutting  can  frequently  be  done  on  the  lathe  under  similar 
circumstances  to  those  referred  to  above.  The  necessary  fixtures 
for  holding  and  indexing  the  work  may  be  comparatively  simple 
and  economical,  a  change-gear  being  frequently  used  as  an  index, 
and  many  jobs  quite  satisfactorily  done  in  the  absence  of  a  regular 
gear-cutting  machine. 

Grinding  is  a  common  operation  in  the  lathe  and  is  referred  to 
in  the  chapter  on  lathe  attachments. 

In  the  absence  of  a  suitable  machine  designed  for  the  purpose, 
cam  cutting  may  be  successfully  done  in  the  lathe,  by  the  use  of 
proper  formers.  The  milling  cutter  for  such  operations  is  carried 
in  the  center  hole  of  the  lathe  spindle,  and  the  cam  held  by  a  suit- 


LATHE   WORK   (CONTINUED)  285 

able  fixture  attached  to  the  compound  rest,  or  to  the  carriage,  as 
may  be  most  convenient. 

The  work  may  thus  be  arranged  so  as  to  cut  face  cams  or  edge 
cams,  and  to  mill  the  cam  slots  of  irregular  contour  on  either  edge 
or  face  cams. 

However,  the  question  of  cams  is  one  of  such  great  variety,  and 
the  devices  necessary  to  properly  handle  them  are  so  many,  a  de- 
tailed discussion  of  ways  and  means  for  doing  the  work  does  not 
seem  proper  in  this  place. 

The  practical  and  resourceful  machinist  will  find  many  uses  for 
the  engine  lathe  that  have  not  been  here  described,  and  if  he  is  a 
progressive  man  he  will  discover  many  new  uses  and  new  devices 
for  handling  the  many  new  kinds  of  work  with  which  he  will  be  con- 
fronted. 

Whatever  new  and  improved  machines  he  may  have  available, 
or  however  well  they  may  be  adapted  to  his  many  wants,  his  prin- 
cipal dependence  will  be  likely  to  be,  in  the  future  as  in  the  past, 
on  the  engine  lathe,  "the  king  of  machine  shop  tools." 


CHAPTER  XV 

ENGINE    LATHES 

Definition  of  the  word  engine.  What  is  meant  by  an  engine  lathe.  The 
plan  of  this  chapter.  The  Reed  lathes.  Reed  18-inch  engine  lathe 
The  Pratt  &  Whitney  lathes.  Their  14-inch  engine  lathe.  Flather 
lathes.  Flather  18-inch  quick  change  gear  lathe.  Prentice  Brothers' 
Company  and  their  16-inch  engine  lathe.  The  Blaisdell  18-inch  swing 
engine  lathe.  The  New  Haven  21-inch  engine  lathe.  Two  lathe  patents 
by  the  author.  The  Hendey-Norton  lathes.  Who  were  the  pioneers 
in  quick  change  gear  devices?  The  Hendey-Norton  24-inch  engine  lathe. 
The  Lodge  &  Shipley  20-inch  engine  lathe. 

A  LARGE  majority  of  the  lathes  in  use  in  the  machine  shop  or 
manufacturing  plant  are  what  have  been  known  for  years  as  engine 
lathes.  Just  why  this  qualifying  designation  of  engine  was  applied 
to  them  is  not  clear,  although  we  know  that  in  former  times  the 
term  engine  was  applied  to  many  machines,  particularly  those  of 
the  higher  class,  and  very  early  in  the  development  of  the  mechanic 
arts  the  word  seems  to  have  been  used  to  designate  almost  any 
kind  of  a  machine.  Thus  we  read  in  the  Marquis  of  Worcester's 
"Century  of  Inventions,"  published  in  1683,  of  "an  engine  that 
may  be  carried  in  one's  pocket"  for  blowing  up  ships;  "a  portable 
engine  in  the  way  of  a  tobacco  tongs";  "an  engine  whereby  one 
man  may  take  out  of  the  water  a  ship  of  500  ton,"  and  so  on, 
showing  the  strange  uses  to  which  the  term  engine  has  been  put 
in  times  past,  while  at  a  comparatively  recent  period  an  indexing 
machine  was  called  a  dividing  engine,  while  Webster  says  broadly 
that  an  engine  is  "a  machine  in  which  the  mechanical  powers  are 
combined." 

Recurring  to  the  subject,  by  the  term  of  engine  lathe  we  mean 
that  class  or  type  of  lathes  which  is  usually  so  denominated  me- 
chanically and  commercially,  and  which  may  be  defined  as  a  metal 
turning  lathe,  having  a  back  geared  head-stock;  a  tail-stock  capable 

286 


ENGINE  LATHES  287 

of  being  set  over  for  turning  tapers;  a  carriage  provided  with  suit- 
able tool-supporting  mechanism  and  having  connected  with  it  an 
apron  carrying  the  necessary  gearing  mechanism  for  producing 
power  lateral  and  transverse  cutting  feeds;  and  a  lead  screw,  with 
suitable  gearing  for  driving  it,  whereby  the  usual  screw  threads  may 
be  cut,  through  its  proper  connection  with  the  apron  mechanism. 

With  this  conception  of  the  design,  construction,  and  office  of 
the  engine  lathe  of  the  present  day,  the  following  examples  are 
presented  and  their  special  features  discussed,  with  a  view  to  the 
better  understanding  of  this  important  machine  tool.  The  en- 
gravings, the  facts  stated,  and  the  dimensions,  where  the  same  are 
given,  are  derived  from  the  machines  themselves  or  their  builders, 
or  both,  and  the  aim  is  to  make  the  information  as  correct  and  the 
estimate  of  their  practical  utility  as  fair  as  is  possible,  so  that  what 
is  here  set  down  will  be  of  value  to  the  buyer  of  these  machines;  to 
the  machinist  who  uses  them;  to  the  draftsman  and  designer  who 
may  desire  to  know  of  their  individual  peculiarities;  and  to  the 
student  who  would  learn  valuable  lessons  in  relation  to  the  design 
and  development  of  the  Modern  American  Lathe. 

While  it  is  not  expected  or  intended  that  the  lathes  of  all  makers 
shall  appear  in  this  connection,  those  of  the  more  prominent  builders 
will  be  introduced,  and  to  these  will  be  added  such  others  as  may 
possess  particularly  commendable  or  novel  features,  in  order  that 
the  essential  points  of  the  engine  lathe  may  be  well  and  thoroughly 
illustrated  and  described,  with  a  minuteness  that  their  importance 
may  demand. 

Among  the  many  manufacturers  of  lathes  the  F.  E.  Reed 
Company  may  deservedly  receive  the  title  of  "ancient  and  honor- 
able," not  because  the  product  of  the  concern  deserves  the  name  of 
ancient,  but  because  of  the  long  and  honorable  career  of  the  estab- 
lishment which  has  always  stood  for  good  materials,  good  work- 
manship, and  practical  design  for  every-day  tools  capable  of 
standing  up  to  the  work,  year  in  and  year  out,  with  whatever  the 
machine  tool  market  affords.  While  the  company  have  always 
built  substantial  and  practical  tools,  of  ample  strength  and  many 
conveniencies  for  the  operator,  they  have  not  been  given  to  the 
exploiting  of  mechanical  fads  and  fancies  or  to  going  to  extremes 
in  any  one  direction. 


288 


MODERN   LATHE   PRACTICE 


As  an  example  of  the  engine  lathe  built  by  this  company,  the 
18-inch  swing  engine  lathe  shown  in  Fig.  223  is  given.  It  will  be 
seen  that  here  is  a  deep  and  strong  bed  supported  upon  the  older 
form  of  legs  instead  of  cabinets.  Upon  the  front  leg  is  a  special 


FIG.  223.  —  18-inch  Swing  Engine  Lathe  built  by  the  F.  E.  Reed  Company. 

cabinet  for  holding  the  change-gears  which  are  of  the  older  form  of 
change-gears  proper,  that  is,  removable.  The  feed  is  by  means  of  a 
belt  upon  the  well-known  three-step  cone,  with  which  is  arranged 
a  change  of  gears  making  six  feeds. 


FIG.  224.  —  Spindle  Box  of  the  Reed 
Lathe  Ready  for  Babbitting. 


FIG.  225.  —  Spindle  Box  of  the  Reed 
Lathe  after  Babbitting. 


The  head-stock  is  heavy  and  strong  and  carries  a  spindle  made 
from  a  crucible  steel  forging  which  runs  in  cast  iron  boxes  lined 
with  genuine  babbitt  metal,  as  shown  in  Figs.  224  and  225. 

In  the  first  of  these  illustrations  is  shown  the  cast  iron  box 


ENGINE  LATHES  289 

properly  milled  out  to  fit  the  housings  of  the  head-stock.  After  this 
operation  it  is  bored  out  and  then  slotted  ready  to  receive  the  bab- 
bitt metal  lining.  It  will  be  noticed  that  these  are  all  " dovetail" 
slots,  the  object  of  this  form  being  to  hold  the  lining  metal  securely 
in  its  place.  The  babbitt  metal  is  cast  into  the  box,  after  which 
it  is  compressed  sufficiently  to  fill  out  any  shrinkage  that  may  have 
occurred  upon  cooling,  and  to  render  it  more  dense  and  durable. 
It  is  then  re-bored,  reamed,  and  hand  scraped,  so  as  to  fit  the  spindle 
as  perfectly  as  possible.  Constructed  in  this  manner  there  is  nothing 
coming  in  contact  with  the  spindle  except  the  babbitt  metal,  which, 
when  finished,  has  the  appearance  shown  in  Fig.  225. 

Experience  has  demonstrated  that  with  proper  care  on  the  part 
of  the  operator  a  box  constructed  in  this  manner  will  last  for  a 
very  long  time,  and,  if  properly  lubricated,  that  the  babbitt  metal 
will  soon  " glace"  over  and  form  one  of  the  best  bearing  surfaces 
obtainable.  The  spindle  is  bored  out  to  If  inches.  The  driving- 
cone  is  of  five  steps,  the  largest  being  12  inches  and  is  adapted  for 
a  2|-inch  belt.  The  carriage  is  of  ample  strength  and  has  a  long 
bearing  upon  the  bed,  and  supports  a  very  substantial  compound 
rest.  The  carriage  is  gibbed  to  the  outside  of  the  bed  both  back 
and  front.  The  apron  is  of  ample  dimensions,  so  as  to  afford  space 
for  large  and  strong  operating  parts,  which  are  few  in  number  and 
simple  in  construction. 

The  feeds  include  an  independent  rod  and  patent  friction  feed. 
Combined  gear  and  belt  feeds  are  furnished  and  also  an  automatic 
stop  motion  in  connection  with  either  type  of  feed.  There  is  also 
provided  a  simple  belt  tightener  device.  The  belt  feeds  are  from 
25  to  95  per  inch  inclusive.  When  a  geared  feed  is  wanted  the 
belt  can  be  removed  and  the  feed  rod  connected  with  an  intermedi- 
ate gear.  Then  by  changing  the  gears  upon  the  feed  stud  of  the 
head-stock,  feeds  may  be  obtained  from  12  to  125  per  inch,  inclu- 
sive. Even  this  range  of  feeds  seems  rather  fine  for  modern  methods 
of  work.  The  lathe  will  cut  seventeen  different  threads  from  2  to 
20  per  inch,  inclusive.  The  rack  and  rack  pinion  are  of  steel  and 
capable  of  disengagement  when  regular  turning  feeds  only  are 
required.  An  " offset"  tail-stock  is  furnished. 

The  net  weight  of  one  of  these  lathes  with  an  8-foot  bed  is  3,080 
pounds,  by  which  it  will  be  seen  that  ample  weight  is  provided  to 


290 


MODERN   LATHE   PRACTICE 


obtain  a  strong  and  rigid  machine.  The  countershaft  is  furnished 
with  patent  friction  pulleys  which  can  be  oiled  while  running,  and 
with  self -oiling  boxes  which  will  run  six  months  with  one  oiling,,  and 
requiring  no  further  attention. 

This  company  make  a  variety  of  different  styles  and  types  of 
lathes,  as  well  as  attachments  and  accessories,  which  will  be  found 
described  and  illustrated  further  on  in  these  pages  and  under  their 
appropriate  headings.  The  reader  is  referred  to  them  for  further 
information. 


FIG.  226.  —  14-inch  Swing  Engine  Lathe  built  by  the 
Pratt  &  Whitney  Company. 

Another  of  the  old  and  reliable  lathe  building  establishments 
is  that  of  the  Pratt  &  Whitney  Company,  which  has  for  many  years 
enjoyed  an  enviable  reputation  as  makers  of  fine  machine  tools. 
While  they  have  been  progressive,  and  have  brought  out  many 
valuable  improvements  they  have  never  been  prone  to  exploit 
mechanical  fads,  or  to  put  on  the  market  comparatively  untried 
devices  of  the  newest  kind  suggested  by  enthusiasts  who  imagined 
them  capable  of  marvelous  results.  They  have  nearly  always  pro- 
duced machines  well  and  carefully  designed,  and  constructed  of 
good  material  and  of  excellent  workmanship. 

While  the  product  of  the  company  has  been  large  and  varied, 
a  great  deal  of  attention  has  been  given  to  producing  good  lathes, 
a  sample  of  which  is  given  in  Fig.  226,  which  is  a  14-inch  swing 
engine  lathe  of  recent  design.  While  rated  as  a  14-inch  lathe  it 


ENGINE  LATHES 


291 


swings  nearly  16  inches  over  the  bed,  and,  as  a  lathe  of  that 
capacity,  is  heavy  and  strong,  with  a  deep  and  heavy  bed  sup- 
ported on  their  well-known  design  of  legs  rather  than  cabinets. 
Still  the  net  weight  of  a  6-foot  bed  lathe  is  2,200,  which  is  very 
heavy  for  a  lathe  of  these  dimensions. 

The  apron  is  shown  in  Fig.  227,  in  which  it  will  be  seen  that  it  is 
of  very  strong  construction,  being  made  with  two  plates  whereby 
the  shafts  have  a  support  at  both  ends.  The  feed  rod  is  carried  in 
double  boxes  in  which  are  carried  right  and  left  worms,  engaging 
the  two  worm-gears  which  operate  the  feed  mechanism.  While  the 
use  of  worms  and  worm-gears  in  a  lathe  apron  cannot  be  commended, 


FIG.  227.  —  Apron  of  the  Pratt  &  Whitney  Lathe. 

and  the  difficulties  which  most  builders  have  found  with  them,  have 
caused  their  use  to  be  discontinued,  this  company  still  retain  them 
and  by  very  good  construction  render  them  successful. 

The  lead  screw  nut  is  well  supported  to  stand  the  strain  to  which 
it  is  put,  and  altogether  the  apron  is  an  excellent  specimen  of  good 
material  and  workmanship.  The  double  plates  are  a  feature  that 
ought  to  be  adopted  in  all  lathe  aprons  as  it  adds  much  to  the 
strength  of  the  mechanism,  holds  the  shafts  well  in  line  by  support- 
ing them  at  both  ends,  and  materially  increases  the  wearing  qual- 
ities of  the  various  parts. 

While  the  various  sizes  as  have  been  given  for  the  lathes  of  other 
builders  are  not  at  hand,  it  may  be  said  that  all  bearings  have  more 
than  usual  diameter  and  length  and  the  boxes  are  accurately  scraped 
to  fit  ground  journals.  The  head-stock  is  massive  and  well  designed 
and  provided  with  a  five-step  cone  pulley. 

The  feed  gearing  is  operated  by  a  two-step  cone,  but  has  com- 


292 


MODERN   LATHE   PRACTICE 


pound  gearing  by  which  a  large  variety  of  feeds  may  be  produced. 
The  thread-cutting  mechanism  provides  for  cutting  from  2  to  92 
threads  per  inch,  and  by  the  use  of  the  translating  gears  will  cut 
all  the  usual  metric  threads. 

Other  lathes  of  different  dimensions  and  types  will  be  illus- 
trated and  described  later  on  in  this  book  and  under  their  appro- 
priate headings.  ,  For  information  of  this  kind  the  reader  is  referred 
to  the  chapters  on  these  subjects. 

The  name  of  Flather  has  been  so  long  and  so  intimately  iden- 
tified with  the  invention  and  the  building  of  machine  tools,  that 


FIG.  228.  —  18-inch  Swing  Quick  Change  Gear  Engine  Lathe, 
built  by  Flather  &  Co. 

in  the  development  of  any  type  of  them  we  naturally  look  for  those 
bearing  this  name.  In  the  improvements  of  the  rapid  change  gear 
devices  we  find  the  names  of  Edward,  Joseph,  Herbert,  and  Ernest, 
each  of  whom  have  added  something  new  to  the  "state  of  the  art." 
In  Fig.  228  is  given  a  front  elevation  of  18-inch  swing  "  quick 
change  gear  lathe/'  which  seems  designed  to  meet  the  latest 
requirements,  and  which  is  powerful,  strong  and  rigid,  and  com- 
bines a  reasonable  degree  of  simplicity  with  accuracy,  ease  of 
operation,  good  workmanship  and  material.  The  head-stock  and 


ENGINE  LATHES  293 

tail-stock  are  fitted  to  the  bed  with  a  V  at  the  rear  and  a  flat 
track  in  front,  thus  permitting  the  cross  bridge  of  the  carriage  to 
be  deep  and  strong.  As  will  be  seen  in  the  engraving,  the  head- 
stock  is  heavy  and  strong  with  ample  housings  for  the  main  spindle 
bearings,  which  are  lined  with  genuine  babbitt  metal,  cast  solid  in 
the  head-stock,  compressed,  then  bored  out  and  scraped  to  an 
accurate  fit  for  the  ground  journals  of  the  spindle,  which  is  made 
of  hammered  crucible  steel.  Its  front  bearing  is  3  inches  in 
diameter  and  4|  inches  long.  The  bore  of  the  spindle  is  1J 
inches. 

The  spindle  cone  is  of  five  steps  and  adapted  for  a  2f-inch  belt, 
or  made  of  four  steps  for  a  3J-inch  belt,  as  may  be  desired. 

The  carriage  is  gibbed  on  the  inside  and  outside  and  has  ample 
bearing  on  the  V's,  while  the  tool  rests  are  unusually  wide  and  long, 
and  are  supported  the  full  length  by  the  carriage,  even  when  turning 
the  largest  diameters. 

The  feed  mechanism  is  of  new  design  and  accomplishes  in  a 
simple  and  durable  manner,  and  with  as  few  gears  as  may  be,  all 
the  results  required  in  the  most  modern  lathe.  In  a  general  way 
it  may  be  described  as  attached  to  the  front  of  the  lathe  in  the 
form  of  a  case  in  which  a  cone  of  nine  gears  is  mounted  upon  a  shaft, 
any  one  of  which  can  be  instantly  engaged  by  simply  moving  the 
lever  in  front  of  the  case.  Upon  another  shaft  located  above  the 
cone  of  gears  and  in  line  with  the  lead  screw  is  a  double  clutch- 
gear  controlled  by  the  small  lever  on  the  top  of  the  gear  case. 
The  shifting  of  this  lever  to  three  different  positions  increases  the 
number  of  changes  obtained  by  the  lower  lever  to  twenty-seven. 
This  number  may  be  doubled  by  sliding  in  or  out  a  gear  at  the  end 
of  the  lathe,  thus  giving  fifty-four  changes  in  all.  An  index 
attached  to  the  front  of  the  gear  case  shows  the  entire  fifty-four 
changes,  so  that  the  operator  may  know  instantly  which  lever  it  is 
necessary  to  move,  and  to  what  position  to  set  it  in  order  to  obtain 
any  of  the  different  threads  or  the  different  cutting  feeds  shown 
upon  the  index,  the  entire  mechanism  being  so  simple  that  the  most 
inexperienced  operator  soon  understands  its  construction  and  its 
operation.  The  standard  threads  from  2  to  128,  including  11J,  and 
feeds  from  7  to  450  per  inch,  are  readily  obtained  without  removing 
a  gear,  while  provision  is  made  by  which  odd  threads  or  feeds  may 


294 


MODERN  LATHE  PRACTICE 


be  had  at  little  trouble  or  expense.  All  the  gears  in  the  gear  case 
are  of  coarse  pitch,  and  being  cut  from  the  solid  are  practically 
unbreakable. 

The  rack  and  pinion  are  cut  from  steel,  as  are  also  all  the  gears, 
studs  and  plates  in  the  apron,  insuring  a  great  degree  of  strength 
and  durability  even  under  the  strains  incident  to  very  heavy  duty. 

This  company  make  the  usual  variety  of  lathes  as  built  by  other 
establishments,  and  all  of  them  are  of  good  workmanship  and  with 
the  well-earned  reputation  for  good  tools. 


FIG.   229.  —  16-inch  Swing  Engine  built  by  the  Prentice  Bros.  Company. 

The  Prentice  Brothers  Company  have  for  years  built  lathes, 
good  lathes,  as  must  be  judged  by  the  fact  that  many  hundreds  of 
them  have  been  sold  and  used  all  over  the  country.  Among  the 
older  and  more  conservative  establishments  turning  out  this  class 
of  work,  they  have  yet  endeavored  to  meet  the  demands  of  modern 
methods,  and  in  Fig.  229  is  shown  one  of  their  16-inch  swing  engine 
lathes,  with  a  quick  change  gear  mechanism  and  an  " offset"  tail- 
stock. 

The  head-stock  is  not  as  massive  as  in  those  of  some  other 
builders,  though  strong  enough  for  most  kinds  of  work  which  the 
lathe  will  be  called  upon  to  do.  The  spindle  is  of  high  carbon  steel, 
with  2J-mch  by  4J-mch  front  bearing  and  a  IJ-inch  hole  in  the 
spindle.  The  spindle  is  driven  by  a  five-step  cone,  arranged  for  a 


ENGINE  LATHES  295 

2J-inch  belt.  The  largest  diameter  of  cone-step  is  10  inches.  The 
spindle  runs  in  hard  bronze  bearings. 

The  quick  change  gear  device  contains  the  "cone  of  gears,"  so 
commonly  used  in  these  devices,  and  also  a  series  of  multiplying 
gears  at  the  end  of  the  head-stock,  by  means  of  which  fifty-five 
changes  may  be  made,  from  2  to  60  threads  per  inch,  and  feed  cuts 
from  10  to  320  per  inch.  All  feeds  are  positive  as  no  feed  belts  are 
used.  The  carriage  and  apron  do  not  seem  to  be  of  sufficient  length 
or  weight  to  stand  up  rigidly  to  very  heavy  cuts  with  the  use  of 
high-speed  tool  steel.  Neither  does  the  bed  seem  to  be  as  heavy, 
at  least  as  deep,  as  we  would  expect  to  find  in  a  modern  lathe 
adapted  to  doing  the  heavy  duty  now  expected  of  such  a  lathe. 
The  lathe  with  a  6-foot  bed  weighs  when  boxed  for  shipment  1,850 
pounds. 

The  "  offset "  tail-stock  is  a  very  useful  feature,  which  is  patented 
by  the  manufacturers  and  about  which  there  has  been  much  dis- 
pute with  other  builders  who  have  made  them  from  time  to  time. 

Other  than  this  feature  and  the  quick  change  gear  device  the 
lathe  appears  to  be  their  regular  and  well-known  product  of  engine 
lathes. 

The  company  make  the  usual  variety  of  engine  lathes  of  special 
design  for  special  work  as  well  as  their  plain  lathes.  These  special 
machines,  as  well  as  various  attachments  and  accessories,  will  be 
illustrated  and  described  in  future  chapters,  later  on  in  this  book, 
and  attention  called  to  their  special  features. 

In  1865  P.  Blaisdell  began  the  building  of  lathes  and  has  con- 
tinued the  business  since.  While  no  great  efforts  seem  to  have 
been  made  to  bring  out  new  and  novel  inventions,  the  Blaisdell 
lathes  have  always  been  known  as  machine  tools,  that  are  well  made, 
reliable,  and  practical. 

In  Fig.  230  is  shown  an  18-inch  swing  lathe  of  their  manufacture, 
that  is  a  good  example  of  their  regujftir  line  of  product. 

The  head-stock  of  this  lathe  has  a  cone  of  five  steps  which  take 
a  2|-inch  belt.  The  spindle  is  made  from  hammered,  cast  crucible 
steel,  and  is  bored  out  to  1J  inches.  The  boxes  are  of  gun  metal  or 
of  cast  iron  lined  with  genuine  babbitt  metal,  as  may  be  preferred. 
The  back  gear  ratio  is  11  to  1,  which  is  high  for  a  lathe  of  this  swing. 

The  lathe  has  a  power  cross  feed  with  micrometer  graduations 


296 


MODERN  LATHE  PRACTICE 


for  the  cross-feed  screw.  There  is  furnished  a  rapid  change  gear 
device  for  feeding  from  13  to  339  per  inch,  and  a  new  and  powerful 
friction  warranted  not  to  slip.  There  is  a  patented  automatic  stop 
on  the  feed  rod.  The  lead  screw  will  cut  threads  from  2  to  23,  in- 
cluding 11}  pipe  thread.  The  net  weight  of  this  lathe  with  an 
8-foot  bed  is  2,400  pounds. 

This  company  make  a  variety  of  lathes  and  lathe  attachments 
and  accessories,  some  of  which  are  shown  later  on  in  this  book,  and 
under  the  appropriate  heading,  to  which  the  reader's  attention  is 
directed  if  interested  in  this  class  of  the  product. 


FIG.  230.  —  18-inch  Swing  Engine  Lathe,  built  by  P.  Blaisdell  &  Co. 

The  New  Haven  Manufacturing  Company  are  among  the  older 
establishments  building  engine  lathes,  and  for  a  number  of  years 
have  built  a  line  of  very  strong  and  substantial  tools,  notable  not 
so  much  for  fine  finish  as  for  rigidity  and  for  practical  utility,  special 
attention  having  been  given  to  the  quality  of  the  materials  entering 
into  them. 

Figure  231  gives  a  front  elevation  of  their  21 -inch  swing  lathe, 
and  Fig.  232  is  an  end  view  of  the  head  and  bed,  showing  the  feeding 
and  thread-cutting  gears.  The  arrangement  of  the  former  is 
peculiar  and  the  subject  of  a  patent  granted  to  the  author.  In  this 
case  there  is  fixed  upon  the  outer  end  of  the  head-shaft  a  "cone  of 


ENGINE  LATHES 


297 


gears,"  with  each  of  which  is  engaged  an  idle  gear  running  loosely 
upon  a  stud  fixed  to  a  revolving  plate,  secured  in  any  desired 
position  by  a  spring  pin  as  shown  in  the  end  view  of  the  lathe. 


FIG.  231.  —  21-inch  Swing  Engine  Lathe,  built  by  the 
New  Haven  Manufacturing  Company. 

When  in  either  of  the  three  operative  positions,  one  of  these  idle 
gears  connects  the  cone  of  gears  on  the  head-shaft  with  a  reversed 
cone  of  gears  running  loose  upon  a  stud  in  an  arm  of  the  stud-plate, 
and  one  of  them  engaging  with 
the  gear  running  loose  upon  the 
lead  screw,  which  gear  in  turn 
engages  with  a  gear  fixed  to  the 
feed  rod.  By  this  arrange- 
ment the  plate  carrying  the 
three  (or  more)  idle  gears  may, 
by  revolving  it  to  any  one  of 
its  several  positions,  succes- 
sively connect  the  different  size 
of  gears  composing  the  cone  of 
gears,  and  so,  at  one  motion, 
changing  the  rate  of  feed.  By 
the  changing  of  a  pin  passing 
through  the  hub  of  the  feed-rod 
gears,  another  series  of  feeds  may  be  obtained.  The  engraving 
shows  a  revolving  plate  carrying  but  three  idle  gears.  It  is  obvious 
that  any  reasonable  number  of  idle  gears  may  be  carried  and  that 


FIG.  232.  — End  Elevation  of  21-inch 
New  Haven  Lathe. 


298  MODERN  LATHE   PRACTICE 

by  the  use  of  multiplying  gears  these  ratios  may  be  had  in  several 
series  of  numbers.  The  object  of  mounting  the  second  cone  of 
gears  upon  a  stud  fixed  in  an  arm  cast  integral  with  the  main  part 
of  the  stud-plate  (shown  in  its  inactive  position)  is  so  that  when 
the  regular  change-gears  are  mounted  upon  the  head-shaft  and 
lead  screw,  and  an  idler  placed  upon  the  idler  stud,  and  the  stud- 
plate  raised  to  an  active  position  for  the  purpose  of  engaging  the 
three  change-gears  thus  mounted,  the  second  cone  of  gears  will 
be  thrown  out  of  their  active  position  and  the  operation  of  the 
feed  rod  stopped.  This  same  device  may  be  applied  to  the  cut- 
ting of  threads  if  desired,  by  the  addition  of  gears  to  the  cone,  and 
the  use  of  multiplying  gears  to  get  ratios  of  2  to  1,  3  to  1,  and 
4  to  1. 

Within  the  head-stock  is  a  device  for  handling  the  reverse 
gears,  consisting  of  a  horizontal  shaft  operated  by  the  handle  seen 
in  the  front  of  the  head,  and  having  upon  it  a  cylindrical  cam  cut 
with  a  groove  consisting  of  two  movements  and  three  rests,  in 
which  is  engaged  a  hardened  steel  pin  fixed  in  the  yoke-plate,  carry- 
ing the  reversing  gears.  By  this  arrangement  the  yoke-plate  is 
readily  locked  in  its  "forward,"  "back,"  and  "out"  positions,  and 
held  perfectly  rigid  when  moved  from  one  position  to  the  other. 
This  device  was  also  invented  and  patented  by  the  author.  Either 
of  these  devices  can  be  operated  while  the  lathe  is  in  motion,  with- 
out danger  of  breaking  the  teeth  of  the  gears. 

These  lathes  have  hollow  spindles  and  the  one  shown  in  the 
engraving  is  made  to  the  following  specifications.  The  beds  are 
wide,  deep  and  strongly  braced  and  mounted  upon  cabinets  of 
liberal  dimensions.  The  width  between  the  V's  is  such  as  to  form 
the  base  of  an  equilateral  triangle,  whose  apex  is  the  center  line  of 
the  lathe.  The  heads  are  very  strong  and  rigid,  having  a  solid 
web  entirely  across  under  the  cone  pulley.  The  spindle  is  bored 
out  to  ^|  inches  and  runs  in  nickel  bronze  boxes.  The  front  bear- 
ing is  3i  inches  in  diameter  and  5J  inches  long.  The  spindles  are 
powerfully  back  geared  and  have  hardened  steel  bushings  and  check- 
nut  for  taking  up  the  end  thrust.  Cone  pulleys  have  five  steps  of  5J 
to  13f  inches  diameter,  and  adapted  for  a  3-inch  belt.  The  tail- 
stock  is  very  rigid,  with  a  "set-over"  for  turning  tapers  and  is 
secured  by  two  heavy  steel  bolts.  The  tail  spindle  is  2f  inches  in 


ENGINE  LATHES  299 

diameter  and  bored  for  a  No.  4  Morse  taper.  The  carriage  is  heavy 
and  has  a  long  bearing  on  the  V's,  to  which  it  is  scraped  and  fitted 
the  entire  length,  and  is  gibbed  at  the  front  and  back  to  the  outside 
of  the  bed.  It  has  power  cross  and  lateral  feeds,  an  automatic  stop 
and  a  compound  rest  with  a  graduated  base.  The  tool  is  adjusted 
as  to  height  by  a  hardened  steel  concave  ring  and  washer.  The 
apron  is  very  heavy,  the  operative  parts  simple  and  very  strong. 
No  worm-gears  are  used,  their  usual  office  being  performed  by  a 
large  bevel  gear  and  two  sliding  bevel  pinions,  by  which  the  motion 
is  reversed.  This  sliding  movement  also  operates  a  simple  locking 
mechanism  by  which  the  thread  cutting  and  feeding  operations 
become  entirely  independent  of  each  other,  and  each,  when  in  opera- 
tion, locks  the  other  out  automatically.  The  six  regular  changes 
of  feed  are  18,  25,  30,  40,  50,  and  60  revolutions  per  inch  of,  move- 
ment for  both  lateral  and  cross  feed.  All  feed  racks,  rack  pinion, 
studs,  rod  and  lead  screw,  are  made  of  special  steel,  and  all  nuts  are 
case  hardened. 

It  will  be  noticed  in  the  engraving  of  the  front  of  the  lathe  that 
all  movements,  including  those  of  reversing,  are  controlled  by  levers 
in  the  front  of  the  apron,  so  that  the  operator  need  not,  necessarily, 
leave  his  place  for  this  purpose. 

A  21-inch  swing  lathe  with  a  10-foot  bed  weighs  3,800  pounds. 

This  company  manufacture  several  other  types  of  lathes  and 
lathe  attachments,  which  will  be  illustrated  and  described  later  on 
in  this  work  and  in  connection  with  similar  devices  built  by  other 
makers. 

It  is  said  in  a  catalogue  now  on  the  author's  desk  that  "the 
name  Hendey-Norton  has  come  to  be  generally  recognized  as  being 
the  pioneer  in  that  class  of  lathes  made  commercially  successful, 
having  the  mounted  system  of  gearing  for  thread  and  feed  changes." 
As  to  how  far  this  claim  is  correct,  is  a  proper  matter  for  the  me- 
chanical public  to  judge.  The  phrase  " commercially  successful" 
seems  to  have  been  well  put  in  connection  with  the  statement  and 
may  possibly  be  its  "saving  grace,"  for  it  is  well  known  that  as 
early  as  1868  Humphreys  used  the  much  discussed  "cone  of  gears," 
and  that  he  wrote  in  his  patent,  "I  place  my  gear-wheels  upon  a 
shaft  A,  ranging  from  the  smallest  to  the  largest,"  while  in  1892 
Norton  says  in  his  patent,  "on  the  shaft  A,  and  within  the  box  B, 


300 


MODERN  LATHE  PRACTICE 


are  secured  a  series  of  gear-wheels  E,  of  varying  diameters,  arranged 
step-like,"  etc.  As  to  who  was  the  pioneer  may  be  an  open  ques- 
tion, as  are  a  great  many  relating  to  the  matter  of  patented  inven- 
tions. 

In  Fig.  233  is  shown  a  front  elevation  of  the  Hendey-Norton 
lathe  of  24-inch  swing,  and  is  a  late  development  of  this  establish- 
ment. The  head-stock  is  provided  with  a  "tie"  from  front  to  rear 
housing,  which  gives  additional  rigidity  to  the  head-stock  and  pre- 
vents undue  vibration  of  the  spindle  and  its  work.  The  spindle, 
which  is  bored  out  to  If  inches,  runs  in  annular  bearings  of  special 


FIG.  233.  —  24-inch  Swing  Engine  Lathe  built  by  the  Hendey  Machine 

Company. 

metal  and  having  taper  bearings  for  the  journals.  The  front  bear- 
ing is  3f  to  4f  inches  in  diameter  and  7^  inches  long,  while  the  rear 
bearing  is  3}  to  4  inches  in  diameter  and  5J  inches  long.  Both 
these  journals  are  not  only  self-adjusting,  but  adjustable,  inde- 
pendent of  each  other,  and  allow  for  contraction  and  expansion  of 
the  spindle  without  disturbing  the  adjustment.  The  bearings  are 
also  self-oiling,  having  automatic  oiling  rings,  running  in  large 
reservoirs  of  oil,  with  provision  for  catching  the  oil  and  returning 
it  to  the  reservoir  for  use  over  again. 

The  construction  of  this  spindle  and  its  appendages  for  the 
smaller  lathes  is  well  shown  in  the  longitudinal  section  given  in 
Fig.  234,  which  shows  a  very  clever  piece  of  mechanical  construc- 
tion and  one  well  adapted  to  the  purposes  for  which  it  is  designed. 


ENGINE  LATHES 


301 


This  view  in  connection  with  the  end  elevation  and  partial  section 
given  in  Fig.  235  shows  the  internal  construction  of  the  feeding 


FIG.  234.  —  Longitudinal  Section  of  the  Head-Stock  of  the 
24-inch  Hendey-Norton  Lathe. 

and  thread-cutting  mechanism  and  the  gearing  necessary  to  accom- 
plish the  results  according  to  Norton's  plan. 

The  lathe  is  provided  for  automatically  stopping  the  carriage 


FIG.  235.  —  End  Elevation  of  the  24-inch  Hendey- 
Norton  Lathe. 

in  either  direction  when  either  feeding  or  thread  cutting,  and  for 
reversing  the  travel  of  the  carriage  by  an  apron  lever. 


302  MODERN   LATHE  PRACTICE 

The  spindle  cone  has  but  four  steps  instead  of  five,  as  is  usual 
with  other  makers,  their  diameters  being  from  6  to  15  inches  and 
adapted  for  a  3|-inch  belt.  The  lathe  will  cut  threads  from  1  to 
56  per  inch  and  has  a  turning  range  of  feeds  from  5  to  280  per  inch. 
The  24-inch  swing  lathe  will  turn  15J  inches  over  the  carriage.  The 
tool-post  takes  in  tools  f  by  1J  inches.  The  carriage  has  a  bearing 
of  34  inches  on  the  bed  and  is  provided  with  a  strong  and  well 
designed  apron,  excepting  for  the  fact  that  worms  and  worm- 
gears  are  still  retained  as  a  part  of  their  construction,  notwith- 
standing the  fact  that  even  the  best  construction  of  this  type  is 
liable  to  injury  from  the  carelessness  of  the  operator  and  the  lack 
of  a  plentiful  supply  of  oil.  The  tail-stock  is  strong  and  rigid,  and 
carries  a  2|-inch  spindle  bored  and  reamed  for  a  No.  4  Morse  taper. 
The  weight  of  a  24-inch  swing  lathe  with  a  10-foot  bed  is  5,450  pounds, 
by  which  it  will  be  seen  that  it  is  relatively  a  heavy  lathe,  consider- 
ably more  so  than  that  of  many  of  its  competitors. 

This  firm  make  other  types  or  modifications  of  their  lathes, 
and  also  some  very  desirable  attachments  and  accessories  for  lathes 
which  are  illustrated  and  described  under  their  appropriate  head- 
ings further  on  in  this  work. 

The  Lodge  &  Shipley  Machine  Tool  Company  have  turned  out 
some  good  examples  of  modern  machine  tool  building,  in  the  recent 
types  of  their  engine  lathes,  showing  much  consideration  and  study 
of  the  conditions  surrounding  the  manufacturing  problems  of  the 
present  day.  This  is  noticeable  in  their  20-inch  swing  engine  lathe, 
a  front  elevation  of  which  is  shown  in  Fig.  236. 

In  this  lathe  the  back  gear  quill  and  pinion  are  of  forged  steel 
instead  of  cast  iron,  as  usual,  whereby  great  strength  and  durability 
may  be  expected  of  this  part,  which  in  ordinary  lathes  not  infre- 
quently fails  and  has  to  be  renewed.  The  cone  pinion  is  also 
of  forged  steel.  The  main  spindle  is  of  55  point  carbon-steel  and 
hammered,  and  has  a  If -inch  hole  through  its  entire  length.  The 
front  bearing  is  3J  inches  in  diameter  and  5|  inches  long,  and  both 
bearings  are  accurately  ground  and  the  boxes  have  an  oil  reservoir 
beneath  them  from  which  oil  is  raised  by  small  buckets  attached 
to  a  brass  ring  located  midway  on  the  journal,  thus  insuring  abun- 
dant lubrication.  Gage  glasses  at  the  front  of  the  head-stock 
show  the  level  of  oil  in  these  reservoirs,  which  are  deep  enough  to 


ENGINE  LATHES 


303 


permit  sediment  to  settle  at  the  bottom  out  of  reach  of  the  oil- 
raising  buckets,  thus  keeping  the  lubricant  on  the  journal  clean  and 
in  good  condition.  The  thrust  collar  is  of  steel,  hardened  and 
ground. 

The  general  arrangement  and  construction  of  the  head-stock, 
and  the  gearing  contained  in  the  front  end  of  the  bed,  is  well  shown 
in  the  longitudinal  section  in  Fig.  237,  and  the  end  elevation  in 
Fig.  238.  In  these  engravings  the  location  of  the  "cone  of  gears" 
is  seen  to  be  in  the  bed  of  the  lathe  instead  of  in  a  box  or  extension 


FIG.  236.  —  20-inch  Swing  Engine  Lathe  built  by  the  Lodge  &  Shipley 

Machine  Tool  Company. 

/ 

in  front  of  it,  or  partially'  in  the  head  as  is  the  case  of  some  of  the 
rapid  change  gear  devices.  In  Fig.  238  the  location  of  the  various 
handles  and  levers  for  controlling  the  change  gear  device  is  clearly 
shown  and  their  use  and  operation  may  be  readily  seen  and  under- 
stood. The  movable  or  sliding  connecting  or  intermediate  pinion, 
carried  by  a  lever  which  is  held  in  place  by  a  spring  pin  entering 
any  one  of  the  line  of  holes  shown  in  the  front  of  the  head-stock  in 
Fig.  236,  is  practically  the  same  as  used  in  the  Hendey-Norton 
lathe  and  in  others  of  this  type.  These  changes  are  very  quickly 
and  certainly  made,  and  the  mechanism  appears  to  be  substantial 
and  durable. 

The  bed  is  designed  with  ample  depth  and  width,  and  is  strongly 


304 


MODERN   LATHE   PRACTICE 


ENGINE  LATHES  305 

braced  internally  by  cross  girts  The  surfaces  to  which  the  lead- 
screw  bearings  are  fastened  are  planed  to  receive  them  and  the 
parts  are  tongued  and  grooved  to  insure  perfect  alignment.  The 
V's  are  rounded  on  top  to  prevent  bruising.  In  lathes  of  22-inch 
swing  and  larger  the  beds  are  additionally  strengthened  by  a  cen- 
tral longitudinal  brace,  in  the  top  of  which  is  a  rack  into  which  a 
pawl  pivoted  to  the  bottom  of  the  tail-stock  engages,  thus  affording 
a  positive  brace  for  holding  the  latter  in  position  against  heavy 
strains.  The  rear  end  of  the  bed  is  cut  down  low  enough  to  permit 
the  ready  withdrawal  of  the  tail-stock,  which  is  very  convenient 
when  turret  slides  or  similar  attachments  are  to  replace  the  regular 
tail-stock. 

The  carriage  is  strong  and  heavy  with  liberal  length  of  bearing 
upon  the  V's  the  entire  length  of  the  carriage,  which  is  gibbed  to 
the  bed  its  entire  length  also.  In  place  of  an  inside  V  at  the  front 
of  the  bed,  the  surface  is  flat  for  the  carriage  to  find  an  additional 
bearing,  thus  shortening  the  distance  between  the  supports  of  the 
carriage  and  so  affording  additional  strength  and  rigidity  immedi- 
ately under  that  portion  supporting  the  compound  rest  in  its  usual 
position.  The  V's  are  kept  clean  and  also  lubricated  by  a  specially 
designed  wiper  and  oiler  fastened  to  the  ends  of  the  carriage. 
This  not  only  insures  the  proper  lubrication  but  prevents  grit  and 
dirt  getting  between  the  carriage  and  the  V's,  and  so  destroying 
their  accurate  bearing  and  smooth  surface  contact. 

The  apron  is  of  ample  strength  and  made  specially  rigid  by  three 
braces  through  its  entire  length  and  a  longitudinal  brace  across 
the  bottom.  It  is  tongued  and  grooved  into  the  carriage,  and 
firmly  bolted  to  it.  No  worm  or  worm-gears  are  used,  a  compact 
arrangement  of  a  large  bevel  gear  and  two  bevel  pinions  mounted 
in  a  sliding  frame  taking  the  place  of  the  older  method  of  construc- 
tion. There  are  few  gears  used  in  this  construction,  and  all  of  them 
are  of  steel  and  run  on  hardened  and  ground  steel  studs  or  shafts. 
The  lead  screw  passes  through  the  double  bevel  pinions,  and  is 
splined  to  them  by  a  spline  reaching  the  entire  length  of  the  gear 
sleeve,  the  edges  of  the  spline  being  carefully  rounded  to  prevent 
the  possibility  of  injuring  the  split  nuts,  which  are  made  from 
solid  metal  and  then  split,  instead  of  being  lined  with  babbitt 
metal  as  usual.  These  nuts  are  held  in  planed  grooves  in  the 


306 


MODERN   LATHE   PRACTICE 


back  of  the  apron,  no  clamps  or  screws  being  used.  This  holds 
them  very  rigidly  under  the  heaviest  strains.  In  the  larger 
lathes  it  is,  of  course,  necessary  to  back  gear  the  operative  parts 
for  ease  of  handling.  This  is  done  with  few  gears,  which  are 
made  heavy  and  strong.  The  lead  screw  threads  are  never  in  use 
except  when  thread  cutting,  the  locking  out  of  the  thread  cutting 
or  the  regular  feed  device  being  automatically  and  surely  provided 


FIG.  239.  —  Apron  of  the  Lodge  &  Shipley  20-inch  Lathe. 

for  by  a  simple  device.  The  rear  of  this  apron  is  shown  in  Fig.  239, 
by  which  its  compact  form  and  mechanical  design  is  clearly  shown. 
This  establishment  builds  other  types  of  lathes  of  very  practical 
and  useful  forms  and  equally  good  design,  as  well  as  various  attach- 
ments and  accessories  which  will  be  found  illustrated  and  described 
further  on  in  this  book  under  their  appropriate  headings,  and  to 
which  the  reader  is  referred  for  information  of  this  character. 


CHAPTER  XVI 


ENGINE   LATHES   CONTINUED 

Schumacher  &  Boye's  20-inch  instantaneous  change  gear  engine  lathe. 
Emmes  change  gear  device.  32-inch  swing  engine  lathe.  Le  Blond 
engine  lathes.  24-inch  swing  lathe.  The  Le  Blond  lathe  apron.  Com- 
plete drawing  of  a  front  elevation.  The  Bradford  Machine  Tool  Com- 
pany's 16-inch  swing  engine  lathe.  The  American  Tool  Works  Company's 
20-inch.  The  Springfield  Machine  Tool  Company's  16-inch  engine  lathe. 
The  Hamilton  Machine  Tool  Company's  18-inch  swing  engine  lathe.  The 
W.  P.  Davis  Machine  Company's  18-inch  swing  engine  lathe.  The  Fos- 
dick  Machine  Tool  Company's  16-inch  swing  engine  lathe. 

THE  firm  of  Schumacher  and  Boye  build  a  line  of  well-designed 
and  practical  engine  lathes,  one  of  which,  called  by  the  makers  their 
"20-inch  instantaneous  change  gear  engine  lathe,"  is  shown  in 
Fig.  240. 


FIG.  240.  —  28-inch  Swing  Instantaneous  Chan^ 
Lathe  built  by  Schumacher  < 


s  Gear  Engine 
Boye. 


It  will  be  noticed  that  the  spindle  cone  has  but  three  steps, 
respectively  9,  11,  and  13  inches  in  diameter,  and  adapted  for  a 
3J-inch  belt.  As  the  head  is  double  back  geared,  the  requisite 

307 


308  MODERN   LATHE   PRACTICE 

number  of  different  speeds  is  obtained,  the  back  gear  ratios  being 
3i  to  1,  and  10  to  1.  The  front  bearing  of  the  main  spindle  is  Si- 
inches  in  diameter  and  6  inches  long.  The  spindle  has  a  lT9g-inch 
hole  through  its  entire  length,  and  reamed  for  a  No.  4  Morse  taper. 

The  change  gear  device  is  the  one  patented  by  Emmes,  in  1902. 
and  is  very  effective  as  a  piece  of  practical  mechanism,  and  is  oper- 
ated by  a  front  and  a  top  lever,  swinging  upon  centers  and  carrying 
index  pins  which  enter  any  one  of  a  circle  of  index  holes.  Sliding 
pinions  are  also  used  upon  the  feed  rod  to  still  further  enhance  the 
value  of  the  mechanism  by  providing  for  the  operating  or  the  dis- 
connecting of  the  feed  rod.  The  reverse  for  both  feeding  and  thread 
cutting  is  handled  at  the  head,  and  in  the  apron,  as  may  be  desired. 
The  cutting  feeds  are  locked  "out"  while  threads  are  being  cut, 
and  vice  versa.  Forty  changes  of  feeds  and  for  thread  cutting  is 
provided  for.  The  apron  is  constructed  on  simple  and  strong 
lines  and  is  effective  in  withstanding  the  strains  and  shocks  to 
which  it  is  subjected.  All  the  gears  in  it  are  made  from  drop 
forgings.  The  lathe  with  an  8-foot  bed  weighs  3,850  pounds. 

This  establishment  makes  lathes  up  to  48-inch  swing,  those  of 
32-inch  swing  and  upward  being  provided  with  triple  geared  head- 
stocks  which  are  built  very  strong,  heavy,  and  rigid.  These  larger 
lathes  all  have  the  " instantaneous  change  gear"  device,  practically 
the  same  as  that  provided  for  the  smaller  lathes.  The  aprons  of 
these  lathes  are  of  the  box  form  and  of  very  rigid  construction, 
avoiding  overhang  as  much  as  possible,  and  also  the  straining  of 
pinions  and  studs.  These  studs  are  made  of  tool  steel  and  run  in 
bronze-lined  boxes.  The  lead  screw  nuts  are  also  of  bronze.  The 
main  spindle,  in  the  head-stock,  is  of  75-point  carbon,  crucible  steel, 
has  a  3J-inch  hole,  and  runs  in  phosphor  bronze  boxes.  It  is 
reamed  for  No.  6  Morse  taper.  The  carriage  has  bearings  through 
ite  entire  length  on  the  V's,  and  is  gibbed  both  back  and  front.  The 
compound  rest  has  an  angular  feed  by  power  with  12  inches  travel. 
The  apron  and  compound  rest  have  steel  gears  throughout.  The 
tail-stock  is  provided  with  a  pawl  which  travels  in  a  rack  formed 
in  the  bed  similar  to  those  shown  by  Lodge  &  Shipley.  The 
48-inch  lathe  will  swing  31  inches  over  the  carriage.  The  lathe 
with  a  14-foot  bed  weighs  17,500  pounds,  and  is  a  very  strong 
and  rigid  lathe. 


ENGINE  LATHES   (CONTINUED)  309 

This  lathe  has  forty  changes  of  feeds  and  also  the  same  number 
for  thread  cutting. 

The  company  make  the  usual  variety  of  lathe  attachments  and 
accessories  necessary  to  fitting  out  their  lathes  with  modern  con- 
veniences, which  will  be  mentioned  later  and  under  headings  that 
follow  this  in  proper  order.  Many  of  these  have  found  their  way 
into  the  best  machine  shops  of  this  country,  and  are  much  appre- 
ciated. 

The  LeBlond  manufacture  of  lathes,  like  their  milling  machines, 
are  well  known  in  the  market,  and  are  noted  for  their  good  and  care- 
ful design  so  as  to  properly  meet  the  requirements  which  they  have 
to  fulfil.  They  are  made  from  a  good  system  of  standard  plugs, 
jigs,  and  templets,  by  which  all  the  component  parts  are  rendered 
interchangeable . 

The  spindles  are  all  made  from  hammered  crucible  steel  and 
finished  by  grinding.  The  boxes  on  the  smaller  lathes  are  com- 
posed of  phosphor  bronze,  while  those  of  the  larger  and  heavier 
lathes  are  lined  with  genuine  babbitt  metal.  The  lead  screws  are 
made  from  20-point  carbon  open  heart*h  steel  and  are  not  splined, 
whereby  the  accuracy  of  the  'screw  is  maintained  for  good  thread 
cutting.  Thread-cutting  stops  are  graduated  in  thousandths  of 
an  inch  and  right  or  left  hand  threads  are  arranged  for  by  a  / 
reverse  in  the  head. 

The  lateral  and  cross  feeds  are  automatic  and  are  properly 
graduated  for  good  work.  The  aprons  are  unusually  heavy  and  so 
arranged  that  it  is  impossible  to  throw  in  the  rod  feed  and  the  lead 
screw  feed  at  the  same  time.  The  rack  pinion  can  be  freed  from 
engagement  with  the  rack  by  lowering  it  out  of  its  engaged  position 
so  that  there  is  no  undue  resistance  when  thread  cutting  is  to  be 
done.  It  frequently  happens  that  much  friction  is  caused  by  these 
strains  upon  the  moving  parts  of  the  apron  and  cause  serious  in- 
convenience and  often  damage  or  breakage  to  the  ports,  particu- 
larly to  the  rack  pinion. 

The  tail-stock  set-over  arrangement  is  graduated  so  that  tapers 
may  be  readily  determined.  They  are  of  the  overhanging  type, 
frequently  referred  to  as  "the  English  style,"  whereby  the  com- 
pound rest  may  be  swung  around  to  a  position  almost  parallel  with 
the  lathe  bed. 


310 


MODERN   LATHE  PRACTICE 


The  feed  cones  on  the  12-inch  to  24-inch  swing  lathes  are  so 
arranged  that  there  are  tighteners  to  apply  to  an  improved  chain- 
feed  device  so  that  there  is  none  of  the  usual  troubles  from  feed 
devices  driven  by  belting.  On  the  larger  lathes  there  is  provided 
an  improved  chain  device,  giving  three  independent  feeds  on  the 
feed  rod,  and  which  can  be  changed  instantly  by  a  lever  in  the 
front  of  the  head-stock. 

While  this  establishment  makes  several  types  of  lathes,  it  will 
be  sufficient  for  our  purpose  here  to  introduce  the  regular  engine 
lathe,  and  that  of  24-inch  swing  is  taken  as  a  good  example  and 
shown  in  Fig.  241,  which  gives  a  front  elevation,  while  Fig.  242 


FIG.  241.  —  24-inch  Swing  Engine  Lathe  built  by  the 
R.  K.  Le  Blond  Machine  Tool  Company. 

is  an  end  elevation  showing  the  change  gearing.    The  general 
description  of  this  lathe  is  as  follows: 

The  range  of  threads  that  can  be  cut  is  from  1  to  16  per  inch. 
The  main  spindle  is  bored  with  a  2^-inch  hole  and  the  front  end 
bushed  for  a  No.  5  Morse  taper.  The  front  bearing  is  4|  inches  in 
diameter  and  8  inches  long.  The  lathe  is  driven  by  a  five-step 
cone,  the  steps  being  from  6  to  17  inches  in  diameter  and  adapted 
for  a  3J-inch  belt.  While  rated  as  a  24-inch  swing  lathe,  it  really 
swings  25J  inches  over  the  bed  and  16  inches  over  the  carriage.  As 
a  10-foot  bed  lathe  takes  in  4  feet  4  inches  between  centers,  it  is 
seen  that  the  head-stock  and  tail-stock  occupy  a  space  of  5  feet 
8  inches  on  the  bed,  giving  the  opportunity  to  make  both  of  these 
important  features  strong,  rigid,  and  massive.  As  a  10-foot  lathe 


ENGINE   LATHES   (CONTINUED) 


311 


weighs  5,900  pounds  net,  it  is  seen  that  the  weight  is  590  pounds 
per  foot.  Countershaft  pulleys  being  16  inches  in  diameter,  and 
for  5-inch  belt  assures  ample  driving  power,  and  which,  run  at  120 
and  165  revolutions  per  minute,  give  a  spindle  speed  of  2}  to  460 
revolutions  per  minute,  which  is  as  wide  a  range  as  would  possibly 
be  needed  in  a  very  large  variety  of  work. 


FIG.  242.  —  End  Elevation  of  24-inch 
Le  Blond  Lathe. 

In  the  end  elevation,  shown  in  Fig.  242,  the  two  stud-plates  and 
the  system  of  change  gearing  is  clearly  shown,  and  a  good  idea  is 
given  of  the  strength  and  stability  of  the  lathe. 

The  operative  parts  of  the  apron  of  the  smaller  sizes  of  Le  Blond 
lathes  is  shown  in  Fig.  243,  by  which  it  will  be  seen  that  they  are 
very  simple,  and  that  therefore  the  parts  may  be  made  of  sufficient 
strength  to  withstand  the  hard  usage  to  which  a  lathe  is  often  sub- 
jected. The  operation  of  this  mechanism  is  so  simple  that  a  de- 
tailed description  does  not  seem  necessary,  although  attention  is 
called  to  the  very  simple  manner  of  locking  the  rod  feed  out  when 
the  lead  screw  feed  is  in  operation,  and  vice  versa. 


312 


MODERN   LATHE  PRACTICE 


As  no  engraving  of  the  exterior  of  a  lathe  can  give  a  proper  and 
correct  idea  of  its  interior  construction,  a  full  and  complete  draw- 
ing of  a  front  elevation  of  this  lathe  is  given  in  Fig.  244,  particularly 
to  illustrate  this  lathe  and  in  a  general  way  to  show  the  construc- 
tion of  a  modern  engine  lathe  of  a  substantial  and  practical  type 
for  heavy,  e very-day  work,  and  showing  its  general  symmetry  and 
good  proportions. 

The  Bradford  Machine  Tool  Company  have  recently  developed 
a  line  of  lathes  which  compare  very  favorably  with  those  of  other 
builders  and  possess  some  excellent  features  of  strength,  durability, 
and  convenience  for  straight,  e  very-day  machine  shop  work. 


FIG.  243.  —  Apron  of  the  24-inch  Le  Blond  Lathe. 

In  the  design  and  construction  of  these  lathes  there  are  several 
noticeable  features  that  may  well  be  mentioned.  None  of  them 
have  cabinet  legs.  The  old-style  belt  feed  is  used  in  nearly  all  of 
them.  One  of  the  exceptions  is  the  16-inch  swing  lathe  which  is 
adapted  for  tool-room  work  and  has  the  rapid  change  gear  device, 
patented  by  Johnson,  which  gives  a  wide  range  of  turning  feeds  and 
thread-cutting  pitches. 

A  front  view  of  one  of  these  lathes  is  given  in  Fig.  245. 

The  reverse  in  the  head-stock  of  these  lathes  does  not  seem  to 
be  particularly  effective.  A  tightening  device  for  the  feed  belt  on 
most  of  these  lathes  is  handy  and  practical.  There  are  other 
special  features  which  will  be  noticed  later  on. 

The  main  spindles  of  these  lathes  are  of  hammered  crucible 
steel  with  adjustable,  taper,  bronze  boxes;  the  journals  (as  well  as  all 
other  cylindrical  bearings  of  the  lathe)  are  ground.  In  the  16-inch 
lathe  the  spindle  is  bored  out  to  1J  inches. 


ENGINE  LATHES  (CONTINUED) 


313 


314 


MODERN   LATHE  PRACTICE 


The  head  cone  is  of  five  steps  and  adapted  for  a  2J-inch  belt. 
The  lathe  swings  lOf  inches  over  the  carriage.  The  carriage  and 
apron  are  of  ample  dimensions  and  the  requisite  strength  for  all 
practical  purposes.  The  lathe  is  back  geared  9J  to  1.  A  6-foot 
lathe  weighs  2,000  pounds. 


FIG.  245.  —  16-inch  Swing  Engine  Lathe,  built  by  the 
Bradford  Machine  Tool  Company. 

This  lathe  will  cut  threads  from  3  to  46  to  the  inch,  and  has  a 
ratio  of  feeds  of  4J  times  the  number  of  threads  per  inch. 

Figure  246  is  a  longitudinal  section  of  the  head-stock,  giving  a 


FIG.  246.  —  Longitudinal  Section  of  the  Head-Stock 
of  thel6-inch  Bradford  Lathe. 

clear  idea  of  the  construction  of  the  spindle,  boxes,  thrust  bearings, 
and  housings,  as  well  as  the  form  and  strength  of  other  parts  of  the 
head-stock.  The  thrush  bearing  is  upon  a  fiber  washer  supported 
by  a  thrust  screw  and  adjusting  nut. 


ENGINE  LATHES   (CONTINUED) 


315 


A  rear  view  of  the  apron  is  shown  in  Fig.  247,  by  which  it  will 
be  seen  that  worms  and  worm-gears  are  avoided  and  the  substantial 
arrangement  of  a  large  bevel  gear  and  double  bevel  pinions,  mounted 
in  a  sliding  form,  takes  its  place.  The  locking  device  for  preventing 
the  interference  of  the  thread-cutting  and  turning  feeds  with  each 
other  is  clearly  shown.  The  smaller  pinions  and  the  large  rack 
gear  are  of  steel  and  the  rack  pinion  is  capable  of  being  withdrawn 
when  thread  cutting  is  being  done. 

The  carriage  is  scraped  to  the  full  bearing  of  its  entire  length 
on  the  V's  and  is  gibbed  at  both  back  and  front  to  the  outside  of 
the  bed.  It  is  made  deep  and  strong  and  has  power  lateral  and  cross 
feeds  in  all  sizes  of  lathes. 


FIG.  247.  —  Apron  of  the  16-inch  Bradford  Lathe. 

This  company  make  a  variety  of  different  types  of  lathes  and 
attachments  for  them,  which  will  be  illustrated  and  described 
under  appropriate  headings  and  later  on  in  these  chapters. 

The  American  Tool  Works  Company  is  a  comparatively  new 
concern  and  is,  therefore,  unhampered  by  old  traditions  and  the 
somewhat  inconvenient  inheritance  which  burdens  some  of  the 
older  manufacturers,  that  is,  an  accumulation  of  old  designs  and 
older  patterns. 

In  Fig.  248  is  given  an  illustration  of  their  20-inch  swing  engine 
lathe,  which  has  a  rigid  and  strong  appearance  and  mechanical 
design  that  speaks  well  for  its  builders,  who  have  evidently  in- 
tended to  make  a  lathe  of  exceptional  productive  capacity,  and 
ability  to  stand  up  to  the  heavy  duty  now  imposed  on  such  tools 


316 


MODERN   LATHE  PRACTICE 


by  the  use  of  high-speed  tool  steels  and  coarse  feeds  for  the  rapid 
reduction  of  the  material. 

The  head-stock  is  massive  and  of  a  symmetrically  rounded  form. 
The  cone  has  five  steps  and  takes  a  belt  of  rather  more  than  the 
usual  width.  The  spindle  is  of  high  carbon  special  steel  and  accu- 
rately ground,  bored  out  with  a  large  hole,  and  runs  in  a  good 
quality  of  anti-friction  metal  boxes,  provided  with  automatic  ring 
oilers. 

The  carriage  is  proportionately  heavy  and  strong,  liberally 
provided  with  T-slots,  and  has  a  flat  top  for  convenience  of  bolting 
down  work  to  be  bored  or  otherwise  machined.  The  bearings  upon 
the  V's  extend  the  entire  length  of  the  carriage.  The  compound 


FIG.  248.  —  20-inch  Swing  Engine  Lathe  built  by  the 
American  Tool  Works  Company. 

rest  is  broad  and  strong  and  well  fitted  with  hand-scraped  surfaces, 
as  are  all  the  sliding  contacts  of  the  lathe. 

The  bed  is  of  deep  box  girder  section.  The  webs  are  well  tied 
together  with  cross  bars  of  box  form,  making  the  bed  very  strong 
and  rigid.  It  is  of  the  "  drop-V  "  pattern,  which  gives  an  additional 
swing  of  about  2J  inches.  The  V's  are  far  apart  and  the  front  tail- 
stock  way  is  flat,  which,  in  connection  with  the  drop-V  construction, 
renders  it  possible  to  add  an  unusual  amount  of  metal  to  the  bridge 
of  the  carriage,  thus  insuring  unusual  stiffness  and  rigidity. 

The  lead  screw  is  located  within  the  bed  and  imparts  motion 
to  the  carriage  directly  under  the  cutting- tool.  This  construction 


ENGINE  LATHES  (CONTINUED)  317 

obviates  much  of  the  tendency  to  twist  or  lift  the  carriage  off  its 
seat  so  common  in  even  the  best  modern  lathes  where  the  lead  screw 
is  located  on  the  outside  of  the  bed  and  pulls  the  carriage  by  its 
connection  with  the  apron.  The  apron  is  tongued  and  grooved  to 
the  carriage  and  secured  by  large  and  substantial  screws.  All 
studs  are  of  tool  steel,  hardened  and  ground.  All  pinions  are  of 
steel  and  are  bushed  with  bronze.  All  gears  are  of  wide  face  and 
coarse  pitch.  The  reverse  feeds  are  not  by  means  of  bevel  gear  and 
two  bevel  pinions,  as  in  most  modern  lathes,  but  by  tumbler  gears, 
suitably  controlled  at  the  front  of  the  apron.  It  is  well  known  that 
bevel  gears  and  pinions  are  broken  by  slipping  in  and  out  of  engage- 
ment when  running.  In  this  lathe  the  bevel  gear  and  pinions  are 
constantly  engaged,  and  therefore  can  be  cut  theoretically  correct 
and  run  in  close  working  contact.  A  separate  splined  rod  is  pro- 
vided for  driving  the  apron  mechanism,  thus  obviating  the  necessity 
of  splining  the  lead  screw,  as  it  is  well  known  that  no  screw  will 
remain  true  after  splining.  The  screw  is  therefore  simply  and  solely 
used  for  thread  cutting  and  as  a  further  precaution  it  is  placed 
inside  of  the  bed  and  has  no  connection  whatever  with  the  apron  or 
its  mechanism. 

The  carriage  slides,  both  upper  and  lower,  are  fitted  with  taper 
gibs  which  are  tongued  and  grooved  into  the  sides,  so  that  no  amount 
of  strain  will  disturb  them.  These  gibs  are  adjusted  by  a  con- 
venient screw  at  each  end.  The  feed  screws  are  provided  with 
micrometer  dials. 

The  thread-cutting  mechanism  is  exceptionally  well  made.  All 
shafts  are  of  high  carbon  steel  and  accurately  ground.  The  four- 
speed  gear  box  is  mounted  on  the  head  end  of  the  bed,  and  by  means 
of  clutch  members,  operated  by  suitable  knobs  conveniently  located, 
four  changes  are  instantly  obtainable.  This,  in  connection  with  a 
cone  of  eleven  gears,  mounted  on  the  inside  of  the  bed,  any  one  pf 
which  can  be  engaged  instantly  by  means  of  a  sliding  tumbler  gear, 
makes  forty  four  changes  obtainable,  without  removing  a  gear. 
The  index  is  well  arranged  and  comparatively  simple  to  under- 
stand, so  that  the  practical  operation  of  this  mechanism  is  more 
simple  and  easy  than  many  of  the  rapid  change  gear  devices. 

The  workmanship  on  these  lathes  is  unusually  good,  and  this 
applies  not  only  to  the  smoothness  and  fineness  of  finished  surfaces, 


318 


MODERN   LATHE   PRACTICE 


but  what  is  of  still  more  importance,  to  good  fits.  That  the  makers 
have  endeavored  to  make  a  particularly  good  lathe  is  evident,  what- 
ever may  be  our  opinion  of  the  design  of  the  "disc  of  gears  "  intro- 
duced into  the  rapid  change  gear  design. 

The  Springfield  Machine  Tool  Company  make  a  variety  of  engine 
lathes  and  special  lathes  for  various  purposes  that  are  unique  in 
some  respects,  and  very  serviceable  lathes  for  a  large  class  of  manu- 
facturing work. 


FIG.  249.  —  16-inch  Swing  Engine  Lathe  built  by  the 
Springfield  Machine  Tool  Company. 

Their  16-inch  engine  lathe  is  shown  in  Fig.  249,  which  is  equipped 
with  rapid  change  gear  device,  reverse  motion  operated  at  the  apron, 
automatic  stop  for  turning  and  thread  cutting,  and  provided  with 
a  friction-geared  head  spindle. 

In  Fig.  250  is  given  an  end  elevation  of  the  lathe,  principally  for 
the  purpose  of  showing  the  rapid  change  gear  device,  which  is  of 
the  type  first  patented  by  Edward  Flather  in  1895,  and  since  used 
to  a  considerable  extent  on  small  lathes  built  by  various  makers  and 
under  several  later  patents,  most  of  which  are  modifications  of 
that  of  Flather. 

The  main  spindle  is  hollow  and  of  hammered  crucible  steel,  with 
large  bearings  running  in  self -oiling  bronze  boxes,  and  is  friction- 


ENGINE  LATHES   (CONTINUED) 


319 


geared  in  a  similar  manner  to  that  of  a  screw  machine  or  turret 
lathe,  which  is  of  considerable  convenience  in  many  classes  of  work. 

The  lead  screw  has  a  telescopically  arranged  extension,  con- 
trolled by  a  hand  lever.  This  extension  of  the  lead  screw  is  re- 
duced at  its  end  to  enter  the  hole  in  the  change-gear,  a  distance 
equal  to  its  width,  before  the  clutches  with  which  the  change-gears 
and  extensions  are  fitted  come  in  contact  with  each  other.  Thus, 
when  one  of  the  change-gears  is  connected  with  the  lead  screw  it 
ceases  to  depend  upon  the  disc  for  support,  but  is  mounted  on  the 
lead  screw  as  substantially  as  if  secured 
by  a  nut  and  washer,  although  it  is  at 
other  times  supported  by,  and  practi- 
cally journaled  in,  the  circular  gear 
box.  As  a  sufficient  range  of  feeds  or 
screw  pitches  cannot  be  obtained  by 
changing  gears  on  the  lead  screw,  only 
provision  is  made  at  the  head-stock  for 
various  ratios  of  speed.  This  is  ac- 
complished by  means  of  three  pairs  of 
gears,  contained  in  cases,  and  giving 
the  ratios  of  1  to  1,  2  to  1,  and  4  to  1; 
and  when  the  latter  two  are  reversed, 
the  ratios  become  1  to  2,  and  1  to  4, 
giving  five  rates  of  speed  for  the  fixed 
pinion  which  engages  with  the  inter- 
mediate gear,  necessary  for  transmit- 
ting the  motion  to  the  gear  on  the  lead  screw. 

As  there  is  only  one  pair  of  gears  that  can  be  used  at  a  time, 
a  receptacle  is  formed  in  the  leg  of  the  lathe  to  receive  the  other 
pairs,  one  being  suspended  from  a  stud  projecting  from  the  rear 
of  this  cabinet,  while  the  other  is  similarly  placed  on  the  inside  of 
the  door,  rendering  either  equally  available  for  use  in  a  moment. 

The  range  of  threads  which  may  be  cut  on  this  lathe  is  from  2  to 
56  per  inch,  and  the  turning  feeds  from  8  to  224  per  inch. 

Every  change  required  to  cut  any  of  the  threads  or  to  produce 
any  of  the  feeds  above  given  can  be  made  while  the  lathe  is  in 
motion. 

While  the  type  of  device  for  rapid  changes  in  speeds  and  for 


FIG.  250.  —  End  Elevation  of 
16-inch  Springfield  Lathe. 


320 


MODERN  LATHE  PRACTICE 


thread  cutting  may  not  appeal  to  those  machinists  who  desire  a 
strongly  built  and  strongly  geared  mechanism,  this  lathe  is  still 
very  useful  on  a  large  variety  of  small  and  medium  sized  work,  of 
which  there  is  usually  a  great  quantity  in  the  modern  factory  or 
machine  shop  devoted  to  this  class  of  work, 

The  same  company  make  various  types  of  useful  lathes,  fixtures, 
and  accessories  that  will  be  referred  to  under  the  proper  headings 
later  on  in  this  book. 

The  Hamilton  Machine  Tool  Company  build  a  commendable 
line  of  engine  lathes  and  seem  to  have  aimed  to  build  machines  of 


FIG.  251.  —  18-inch  Swing  Engine  Lathe  built  by  the 
Hamilton  Machine  Tool  Company. 

good  design  and  construction,  combining  the  later  features  that 
are  demanded  by  modern  methods  of  machine  shop  and  factory 
requirements  for  accurate  and  rapid  work  as  well  as  a  wide  range  of 
product. 

The  later  designs  of  this  company  are  heavy  and  rigid,  yet  with 
proper  appreciation  of  the  proportioning  of  the  component  parts, 
the  machine  does  not  have  the  clumsy  or  overloaded  appearance 
sometimes  seen  in  heavy  lathes. 

As  a  sample  of  their  modern  lathes  their  18-inch  swing  engine 
lathe  is  shown  in  Fig.  251.  The  bed  is  deep  and  wide  and  well 
braced  to  resist  strains.  It  is  supported  upon  cabinets  of  modern 


ENGINE  LATHES   (CONTINUED)  321 

design,  affording  ample  cubpoard  room  for  storing  tools  and  small 
parts.  The  pads  for  the  lead  screw,  feed  rod  and  reversing  rod 
bearings  are  grooved  and  the  bearings  planed  to  fit  them,  thus  assur- 
ing true  and  permanent  alignment. 

The  head-stock  is  massive  and  of  good  design,  insuring  rigidity 
and  preventing  vibration  and  chatter  even  on  the  heaviest  work 
which  the  lathe  will  be  called  upon  to  perform.  The  spindle  is  of 
high  carbon  steel  forging  and  bored  out  If  inches.  It  is  ground 
its  entire  length  and  runs  in  phosphor  bronze  bearings,  hand- 
scraped  to  fit  the  spindle.  Anti-friction  thrust  bearings  are  pro- 
vided with  an  adjusting  nut  for  taking  up  lost  motion  due  to  wear. 
On  this  lathe  these  bearings  are  provided  with  hardened  and  ground 
steel  washers.  On  the  22-inch  swing  and  larger  lathes  these  bear- 
ings are  provided  with  hardened  and  ground-steel  balls  which  are 
also  adjustable  and  reduce  the  friction  to  a  minimum,  the  ball-races 
being  of  tool  steel  and  also  hardened  and  ground. 

The  spindle  cone  has  five  steps,  the  largest  being  12  inches 
diameter,  and  adapted  for  a  2f-inch  belt.  Readily  removable 
gear  guards  protect  the  face  gear  and  the  back  gear  from  injury 
by  chips,  dirt,  etc.,  and  the  operator  from  the  danger  sometimes 
resulting  from  these  exposed  parts. 

The  tail-stock  is  of  the  "  off  set"  pattern,  that  is,  cut  away  in 
front  so  as  to  permit  the  compound  rest  to  swing  around  parallel 
to  the  V's  of  the  lathe.  The  tail  spindle  is  2^  inches  in  diameter, 
and  is  graduated  for  convenience  in  drilling.  It  is  of  steel  and 
accurately  ground  and  has  an  unusually  long  movement.  The 
tail-stock  has  the  usual  set-over  adjustment  for  turning  tapers. 

The  carriage  is  massive  and  strong,  and  is  gibbed  at  the  front, 
back  and  center,  and  is  scraped  to  a  solid  bearing  upon  the  bed, 
throughout  its  entire  length.  It  is  entirely  flat  on  top  and  amply 
provided  with  T-slots,  so  that  work  to  be  bored  or  otherwise  ma- 
chined can  be  as  readily  clamped  upon  it  as  upon  the  table  of  a 
planer  or  milling  machine.  The  cross-feed  screw  has  a  micrometer 
attachment,  by  .means  of  which,  not  only  can  turning  and  thread 
cutting  be  much  facilitated,  but  the  drilling  of  jigs  and  fixtures 
may  be  as  readily  done  here  as  on  a  milling  machine,  so  far  as  laying 
off  accurate  distances  is  concerned,  by  strapping  the  work  to  an 
angle-plate  bolted  down  to  the  carriage. 


322  MODERN   LATHE   PRACTICE 

In  addition  to  the  above  feature,  the  lathe  is  provided  with  a 
rotating  indicator  or  chasing  dial,  located  on  the  top  of  the  carriage, 
which  enables  the  operator  to  catch  the  thread  quickly  and  properly 
without  reversing  the  forward  motion  of  the  lathe;  and  permitting 
him  to  return  the  carriage  quickly  to  the  starting-point  by  hand. 

The  compound  rest  is  large  and  heavy  with  broad  wearing  sur- 
faces accurately  fitted  by  hand  scraping,  and  provided  with  taper 
gibs.  The  swivel  is  graduated  in  degrees  so  that  it  can  be  quickly 
set  at  any  required  angle.  The  tool-post  is  formed  from  a  solid 
steel  bar  and  has  a  tool  steel  screw. 

The  apron  is  large  and  strong,  and  is  fitted  to  the  carriage  by  a 
tongue  and  groove.  The  operative  parts  are  heavy  and  strong. 
The  rod  feed  and  the  thread  cutting  by  the  lead  screw  are  inde- 
pendent, and  each,  when  in  use,  locks  the  other  out  of  the  possibility 
of  becoming  engaged,  thus  preventing  the  liability  of  breakage 
from  this  source.  The  feeds  are  driven  by  a  powerful  friction  de- 
vice and  are  readily  reversible  at  the  apron  by  a  single  movement. 

An  automatic  stop  is  provided  by  the  addition  of  a  rod  running 
the  entire  length  of  the  bed,  and  which  operates  equally  well  when 
feeding  in  either  direction.  It  operates  with  either  the  turning 
feed  or  with  thread  cutting,  and  enables  the  operator  to  chase  up 
to  a  shoulder,  by  which  feature  it  is  very  useful  in  cutting  internal 
threads,  or  in  boring  to  a  certain  fixed  depth.  It  can  also  be  set 
to  prevent  the  carriage  running  against  either  the  head-stock  or 
tail-stock,  and  is  therefore  a  safety  device  against  the  serious  acci- 
dents that  sometimes  occur  from  this  cause.  This  device  is  of  great 
advantage  in  duplicating  work  such  as  the  turning  of  shafts  having 
one  or  several  shoulders,  as,  the  cut  once  fixed,  the  stop  collar  may 
be  set  and  no  further  attention  paid  to  the  location  of  the  shoulders 
than  would  be  necessary  in  an  automatic  machine. 

The  quick  change  gear  device  by  which  a  large  number  of  threads 
of  different  pitches  are  cut,  and  by  which  a  wide  range  of  turning 
feeds  are  obtained,  contains  the  "disc  of  gears"  or  circular  case, 
containing  eight  change-gears  and  constructed  upon  the  plan  first 
invented  and  patented  by  Edward  Flather  in  1895.  In  addition 
to  this  device  the  usual  multiplying  gears  are  used,  being  contained 
in  another  case  which  properly  protects  them.  This  device  is 
shown  in  the  accompanying  illustrations,  in  which  Fig.  252  is  an 


ENGINE  LATHES   (CONTINUED) 


323 


end  elevation  and  Fig.  253,  a  vertical,  longitudinal  section,  showing 
the  general  design  of  the  mechanism,  which  appears  considerably 
complicated  and  hardly  as  strong  as  such  a  device  ought  to  be  in 
order  to  withstand  the  strains  to  which  it  is  usually  subjected,  and 
therefore  liable  to  get  out  of  order.  The  device  is  well  made  and 
of  good  material,  and  will,  no  doubt,  give  as  good  results  as  may 
be  expected  from  this  form  of  rapid  change  gearing.  It  will  cut 
48  different  threads  from  1  to  56  per  inch,  and  cutting-feeds  from 
6  to  336,  all  inclusive,  by  the  use  of  three  removable  change-gears. 
The  method  by  which  the  various  changes  are  made  is  necessarily 


FIG.  252. —  End  Elevation  of 
the  18-inch  Hamilton  Lathe. 


FIG.   253.  —  Longitudinal  Section  of 
Gearing  of  18-inch  Hamilton  Lathe. 


complicated,  and  in  the  hands  of  an  inexperienced  operator  might 
lead  to  mistakes.  This  can  be  said  of  several  of  the  similar  devices 
built  by  other  establishments. 

The  weight  of  the  18-inch  swing  by  8-foot  bed  lathe  is  2,580 
pounds,  by  which  it  will  be  seen  that  there  has  been  no  stinting  of 
material  in  its  design. 

This  company  build  a  variety  of  lathes  and  attachments  and 
accessories  for  the  same,  which  are  illustrated  and  described  under 
appropriate  headings  later  on  in  this  book,  and  to  which  the  reader 
is  referred  for  information  concerning  them. 

The  W.  P.  Davis  Machine  Company  make  a  general  line  of 


324 


MODERN  LATHE   PRACTICE 


plain  engine  lathes,  of  which  a  good  example  is  shown  of  their  18- 
inch  swing  lathe  in  Fig.  254.  The  bed  is  of  ample  depth  and  well 
proportioned,  and  is  supported  on  the  older  design  of  legs  instead 
of  cabinets. 

The  head-stock  is  of  ample  dimensions  and  has  a  crucible  steel- 
forged  spindle  with  a  Ig^-inch  hole  through  its  entire  length,  and 
runs  in  phosphor  bronze  boxes,  reamed  and  hand  scraped.  The 
front  bearing  is  3  inches  in  diameter  and  5  inches  long.  The  spindle 
cone  has  five  steps,  the  largest  being  11  inches  in  diameter  and 
adapted  for  a  2J-inch  belt. 


FIG.  254.  —  18-inch  Swing  Engine  Lathe,  built  by  the 
W.  P.  Davis  Machine  Tool  Company 

The  feed  is  belt-driven  by  the  usual  three-step  cone,  an  arrange- 
ment for  tightening  the  belt  and  multiplying  gears  whereby  six 
different  feeds  may  be  obtained.  The  change-gears  are  such  as 
will  cut  threads  from  2  to  32  per  inch  inclusive. 

The  carriage,  apron,  tool-rests,  etc.,  are  of  ample  dimensions 
for  the  requisite  strength.  This  lathe  with  an  8-foot  bed  weighs 
2,460  pounds,  a  fair  weight  for  a  manufacturing  lathe  of  these  dimen- 
sions, which  has  evidently  been  the  aim  of  the  builders  to  produce. 

The  same  firm  make  other  types  of  lathes  which  are  illustrated 
and  described  in  future  pages  and  under  their  appropriate  headings. 
Some  of  them  have  special  features  to  which  the  attention  of  the 
reader  is  particularly  directed. 


ENGINE  LATHES   (CONTINUED) 


325 


The  Fosdick  Machine  Tool  Company,  better  known  as  builders 
of  radial  drills,  have  recently  commenced  the  construction  of  lathes 
also,  and  the  one  shown  in  Fig.  255  is  entitled  to  special  considera- 
tion as  the  aim  of  the  makers  evidently  is  to  produce  a  lathe  for 
practical  use  that  will  meet  the  demand  for  a  good  lathe  at  a  reason- 
able price.  This  lathe  is  equipped,  as  illustrated,  with  feed  box  and 
with  compound  rest.  The  bed  is  made  in  different  lengths  from 
6  to  12  feet,  with  cabinet  or  regular  legs,  and  with  or  without  oil 
pan.  The  spindle  bearings  are  2J  and  2J  inches  diameter;  there  is  a 
l^-inch  hole  through  the  spindle,  and  draw-in  chucks  are  furnished 


FIG.  255.  —  16-inch  Swing  Engine  Lathe  built  by  the 
Fosdick  Machine  Tool  Company. 

when  required.  The  bearings  are  bronze  bushed  throughout,  and 
constant  lubrication  is  afforded  through  an  endless  chain  and  large 
oil  pockets.  Owing  to  the  design  of  the  head,  a  three-step  driving 
pulley  may  be  used  in  place  of  the  five-step  cone,  insuring  a  more 
powerful  spindle  drive  when  required  for  high-speed  steel  work. 

The  carriage  has  bearing  surfaces  of  ample  length  and  width  on 
the  shears,  and  the  apron  is  of  the  box-section  type,  insuring  strength 
and  stiffness.  The  design  of  the  tail-stock  is  clearly  shown,  and 
also  that  of  the  follow-rest.  The  compound  rest  is  designed  to 
receive  a  heavy  tool-post.  The  compound  feed  box  shown  is  the 
well-known  Emmes  device,  giving  forty  changes,  the  screw-cutting 


326  MODERN  LATHE  PRACTICE 

feeds  ranging  from  2  to  56  threads  per  inch,  and  the  feeds  for  turning 
being  just  one  fourth  as  coarse. 

The  taper  attachment  can  be  placed  on  any  of  the  lathes  with- 
out changing  the  bed  or  fitting  it  with  brackets,  and  a  turret  of 
pentagon  form,  for  the  carriage,  can  be  furnished  when  desired. 

All  screws  on  any  part  of  the  lathe  requiring  adjustment  are 
operated  with  the  tool-post  wrench.  The  friction  countershaft  has 
self-oiling  bearings  and  oil  wells  are  formed  in  the  friction  pulleys. 

The  swing  over  bed  is  16}  inches,  and  over  carriage  10}  inches. 
With  the  6-foot  bed,  the  length  taken  between  the  centers  is  34 
inches.  The  width  of  the  five-step  cone  pulley  face  is  2f  inches, 
and  of  the  three-step  3|  inches.  The  countershaft  speed  with  five- 
step  cone  is  120  revolutions  per  minute,  and  with  three-step  cone 
250  revolutions  per  minute.  The  weight  of  the  lathe  with  6-foot 
bed  is  2,000  pounds,  which  is  ample  for  a  lathe  of  these  dimensions, 
and  considerably  above  the  average. 


CHAPTER  XVII 

HEAVY   LATHES 

The  Bradford  Tool  Company's  42-inch  swing  triple-geared  engine  lathe. 
The  American  Tool  Works  Company's  42-inch  swing  triple-geared  engine 
lathe.  The  New  Haven  Manufacturing  Company's  50-inch  swing  triple- 
geared  engine  lathe.  The  Niles  Tool  Works  72-inch  swing  triple-geared 
engine  lathe.  The  Pond  Machine  Tool  Company's  84-inch  swing  engine 
lathe. 

THE  42-inch  swing  triple-geared  lathe,  built  by  the  Bradford 
Machine  Tool  Company,  is  a  good  example  of  a  well  designed  and 
massive  lathe  for  the  heaviest  work  to  which  a  lathe  of  this  char- 
acter will  be  subjected.  With  the  severe  requirements  of  modern 
shop  methods  and  the  use  of  high-speed  steels  the  problem  confront- 
ing lathe  builders  has  been  one  to  tax  their  utmost  energies  in  the 
way  of  good  design  scientifically  and  practically  worked  out;  good 
materials  lavishly  applied;  and  good  workmanship  in  every  part. 
Without  all  of  these  in  a  marked  degree  a  lathe  may  scarcely  be 
classed  as  modern. 

As  to  how  well  the  designers  and  builders  of  the  Bradford  lathe 
have  succeeded  in  their  conditions  is  to  a  considerable  extent 
manifest  by  an  inspection  of  the  illustration  given  in  Fig.  256  and 
a  study  of  the  description  which  follows,  as  well  as  to  some  detailed 
engravings  illustrating  the  special  features  of  the  machine. 

The  head-stock  is  long  and  massive,  occupying  over  five  feet 
on  the  head  end  of  the  bed,  affording  large  housings  for  the  spindle 
boxes  and  ample  space  for  broad-faced,  heavy  back  gears,  and  a 
five-step  cone  of  from  10J  to  22  inches  in  diameter  and  5|  inches 
face.  The  spindle  is  of  crucible  steel  and  is  bored  out  with  a  3-inch 
hole.  It  has  a  front  bearing  6  inches  in  diameter  and  10  inches 
long,  and  a  rear  bearing  5  inches  in  diameter  and  9  inches  long. 
The  bearings  are  accurately  ground  and  run  in  heavy  bronze  boxes, 
which  are  reamed  and  hand-scraped  to  a  fix, 

327 


328 


MODERN  LATHE  PRACTICE 


It  was  probably  not  an  Irishman  who  wrote  in  the  manufac- 
turer's catalogue  that  "  the  back  gears  are  conveniently  located  in 
front,"  however  much  it  may  sound  like  it,  as  it  is  a  mechanical 
fact,  and  being  so  located  applies  the  power  at  the  proper  point. 


FIG.  256.  —  48-inch  Swing  Engine  Lathe  built  by  the 
Bradford  Machine  Tool  Company. 

Being  triple  geared  there  are  fifteen  speeds,  increasing  in  proper 
geometrical  progression,  and  the  lathe  is  provided  with  three  rapid 
changes  of  feed  for  each  speed. 


FIG.  257.  —  Head-Stock  of  the  48-inch  Swing  Bradford  Lathe. 

The  coarse  screw-cutting  arrangement  is  shown  at  the  left  of 
the  engraving,  Fig.  257,  and  is  a  regular  device  on  these  lathes.  It 
consists  of  a  short  intermediate  shaft  in  the  outer  end  of  the  head- 
stock,  running  in  a  sleeve  adapted  to  be  moved  longitudinally. 
On  each  end  of  this  shaft  is  fixed  a  spur  gear,  and  when  the  shaft  is 


HEAVY  LATHES 


329 


shifted  to  its  outward  position,  the  gear  on  the  outer  end  of  the 
lathe  spindle  communicates  motion  to  the  screw.  When  this  shaft 
is  at  its  inward  position,  motion  is  communicated  from  the  cone 
gear  in  a  ratio  of  8  to  1.  So  that  if  the  lathe  is  geared  ordinarily 
to  cut  one  thread  per  inch  with  the  outer  gears  engaged,  ft  will, 
with  the  inner  gears  engaged,  cut  a  thread  eight  times  as  coarse,  or 
one  thread  in  8  inches.  In  cutting  very  coarse  threads  the  back 
gears  are  always  used.  Running  in  this  manner  the  strain  is  taken 
off  the  change-gears,  and  threads  or  spirals  as  coarse  as  one  turn  in 
16  inches  can  be  cut. 

In  Fig.  258  is  shown  the  nest  of  gears  attached  to  the  front  of 


FIG.  258.  —  Lead  Screw  Gearing  for  the  48-inch 
Swing  Bradford  Lathe. 

the  bed.  The  three  upper  gears  are  fast  to  the  lead  screw,  while 
the  three  lower  $ears  are  engaged  consecutively  by  a  sliding  key, 
controlled  by  the  nut  shown  at  the  right  of  the  engraving,  and 
handled  by  a  wrench.  These  gears  are  of  steel  and  may  be  engaged 
and  disengaged  while  in  motion. 

The  apron  is  massive  and  well  constructed.  A  rear  view  of  it  is 
shown  in  Fig.  259,  by  which  it  will  be  seen  that  it  is  very  simple, 
and  therefore  the  parts  may  be  made  of  ample  strength.  All  shafts 
have  bronze-bushed  bearings.  Independent  frictions  are  used  for 
both  lateral  and  cross  feeds,  and  are  reversed  from  the  front  of  the 
apron. 

The  lead  screw  is  splined  to  drive  the  two  bevel  pinions,  and  its 
thread  is  only  used  when  cutting  threads.  The  halves  of  the  lead 


330 


MODERN  LATHE  PRACTICE 


screw  nut  are  operated  by  the  usual  form  of  cam,  controlled  by  a 
lever  shown  at  the  right  hand  of  the  apron  in  the  front  view,  as  in 
Fig.  256.  The  end  of  the  sliding  rod  which  carries  the  forks  for 
moving  the  bevel  pinions  is  extended  to  the  lead  screw  nut,  where 
an  attachment  is  made  for  locking  the  lead  screw  nut  open  when- 
ever either  bevel  pinion  is  engaged  with  the  driving  bevel  gear,  and 
for  locking  both  of  these  bevel  pinions  out  of  engagement  whenever 
the  lead  screw  nut  is  closed,  thus  preventing  the  two  types  of  feed 
being  thrown  in  at  one  time.  The  rack  pinion  is  adapted  to  be 
withdrawn  from  engagement  with  the  rack  when  thread  cutting 
is  being  done. 

The  carriage  is  very  long,  deep,  and  massive,  and  is  gibbed  both 
front  and  back.    It  has  a  bearing  of  48  inches  on  the  V's,  and  is 


FIG.  259.  —  Rear  View  of  Apron  of  the  48-inch  Swing  Bradford  Lathe. 

hand-scraped  to  an  accurate  fit.  The  inside  V's  of  the  bed  are 
lower  than  the  outside  V's,  by  which  construction  the  bridge  of  the 
carriage  may  be  made  much  thicker  and  stronger,  thus  adding 
materially  to  the  strength  of  the  carriage  at  the  point  where  it  is 
usually  the  weakest. 

The  compound  rest  is  large  and  broad,  with  an  ample  tool  block 
with  heavy  tool  clamping  bars,  and  having  an  angular  power  feed 
of  12  inches  in  any  direction.  The  base  is  graduated  and  both  top 
and  bottom  slides  are  provided  with  taper  gibs  and  adjusting 
screws. 

The  tail-stock  is  of  ample  dimensions  with  a  bearing  26  inches 
long  on  the  bed.  The  tail-stock  spindle  is  4J  inches  in  diameter 


HEAVY   LATHES 


331 


and  has  a  travel  of  16  inches.  It  has  the  usual  set-over  screw  for 
use  in  turning  taper  work,  and  is  provided  with  a  rack  and  pinion 
device  for  conveniently  moving  it  to  any  desired  point  on  the  bed. 

This  lathe  made  with  a  12-foot  bed  weighs  16,500  pounds,  by 
which  its  massive  design  and  great  strength  may  be  judged  and 
by  which  the  points  stated  in  the  opening  sentences  of  this  descrip- 
tion may  be  more  readily  appreciated. 

The  American  Tool  Works  Company  have  recently  designed  an 
excellent  42-inch  swing  lathe  intended  for  heavy  work  and  having 
a  number  of  good  features  not  usually  found  in  lathes  of  this  capac- 
ity. An  illustration  of  this  lathe  is  shown  in  Fig.  260,  which  gives 
a  good  idea  of  its  massive  design  and  symmetrical  outline. 


FIG.  260. 


42-inch  Swing  Triple-Geared  Engine  Lathe  built  by  the  American 
Tool  Works  Company. 


The  head-stock  is  large  and  massive  with  ample  housings  for 
the  spindle  boxes,  which  are  of  phosphor  bronze  carefully  fitted  to 
the  high  carbon  hammered  steel  spindle,  which  is  accurately  ground 
and  which  carries  a  five-step  cone.  As  the  head  is  triple  geared, 
this  gives  fifteen  speeds  arranged  in  correct  geometrical  progression. 

The  carriage  is  very  heavy  and  strong,  long  bearing  on  the  V's, 
and  made  with  a  flat  top  so  as  to  be  convenient  for  bolting  down 
work  to  be  bored.  The  compound  rest  is  equally  strong  and  pro- 
vided with  heavy  clamping  straps  for  holding  down  the  tools. 

The  feed  is  driven  through  a  quick  change  gear  mechanism  which 
provides  thirty-two  changes  for  feeding  and  thread  cutting,  the 
range  of  threads  being  from  1  thread  in  4  inches  to  16  threads  per 
inch,  including  11 J  pipe  thread.  The  feed  range  is  from  6.4  to  92 
cuts  per  inch. 


332 


MODERN   LATHE  PRACTICE 


The  device  is  operated  while  the  machine  is  running,  if  necessary, 
by  a  revolving  nut  seen  at  the  right  of  the  gear  box  beneath  the 
head,  which  moves  a  sliding  key  engaging  two  opposite  gears,  each 
being  one  of  a  cone  of  gears  which  is  encased  in  the  gear  box.  The 
feed  or  screw  pitches  thus  obtained  are  multiplied  by  the  compound 
gears  on  the  quadrant  at  the  end  of  the  head,  it  being  necessary  to 
change  one  gear  only  on  the  quadrant  for  each  additional  thread. 

This  arrangement  gives  flexibility  to  the  screw-cutting  mechan- 
ism, making  it  possible  to  cut  an  unlimited  number  of  sizes  of 
threads  or  worms,  either  finer  or  coarser  than  the  range  indicated 
above.  An  index  plate  is  provided  to  assist  in  obtaining  the  desired 
feed  or  pitch.  The  feed  may  be  reversed  in  the  apron,  a  feature 
which  is  valuable  on  a  long  lathe  where  the  tool  may  be  working 
at  some  distance  from  the  head-stock. 


FIG.  261.  — ->  50-inch  Swing  Triple-Geared  Engine  Lathe,  built  by  the  New 
Haven  Manufacturing  Company. 

The  New  Haven  Manufacturing  Company  build  a  50-inch  swing 
engine  lathe  that,  while  it  is  a  comparatively  plain  and  simple  lathe, 
furnishes  as  good  a  tool  at  the  price  as  any  in  the  market.  The 
effort  has  been  made  to  build  a  very  massive  and  substantial  lathe 
without  unnecessary  complication  or  finish.  This  lathe  is  shown  in 
Fig.  261. 

The  head-stock  is  very  heavy  and  well  designed,  and  carries  a 
forged  crucible  steel  spindle  with  a  front  bearing  8  inches  in  diam- 
eter and  12  inches  long,  and  a  rear  bearing  6  inches  in  diameter 
and  9  inches  long,  and  running  in  cast  iron  boxes  lined  with  genu- 
ine babbitt  metal  that  is  peinned  in,  bored,  reamed,  and  scraped. 
The  driving-cone  has  five  steps,  ranging  from  lOf  to  19|  inches, 
and  adapted  for  a  4-inch  belt.  The  head  is  triple  geared,  giving 


HEAVY  LATHES  333 

fifteen  changes  of  speed.  All  the  gears  are  broad  and  of  coarse 
pitch,  giving  ample  driving  power.  The  face-plate  is  heavy  and 
well  ribbed,  and  keyed  to  the  nose  of  the  spindle,  and  has  a  broad- 
faced  internal  gear  bolted  to  its  rear  side,  from  which  it  is  driven 
by  a  steel  pinion. 

The  tail-stock  is  constructed  with  a  double  set  of  holding-down 
bolts,  by  which  means  the  upper  bolts  may  be  loosened  and  the 
tail  center  set  over  for  turning  tapers  without  blocking  up  the  work 
or  danger  of  its  dropping  out  of  the  centers.  The  tail  spindle  is  5 
inches  in  diameter  and  reamed  for  a  No.  6  Morse  taper.  The  opera- 
ting hand  wheel  is  directly  in  front  of  the  operator  and  is  back 
geared  to  the  spindle  in  a  ratio  of  3  to  1,  so  as  to  be  easily  and  con- 
veniently operated.  A  back  geared  rack  and  pinion  device  permits 
the  tail-stock  to  be  easily  moved  to  any  desired  position  on  the  bed. 

The  carriage  is  very  heavy  and  strong,  gibbed  front  and  back, 
with  an  unusually  long  bearing  upon  the  bed,  and  carries  a  massive 
compound  rest  with  a  long  angular  feed  in  all  directions^  a  gradu- 
ated base  and  large  hardened  straps,  supported  by  spiral  springs 
upon  studs,  for  holding  the  tool.  These  straps  have  projecting  ends 
so  that  tools  may  be  held  outside  of  the  studs,  which  may  be  placed 
either  crosswise  or  lengthwise  of  the  tool  block  as  may  be  most 
convenient  for  the  work  being  done. 

The  apron  is  built  with  double  plates  so  as  to  give  shafts  and 
studs  a  bearing  at  each  end.  All  feeds  are  reversible  at  the  apron. 
A  large  bevel  gear  with  two  bevel  pinions  is  provided  in  the  apron, 
and  an  automatic  locking  mechanism  prevents  turning  feeds  and 
thread-cutting  feed  from  being  engaged  at  the  same  time.  As  an 
extra  precaution  against  the  frictions  binding  and  refusing  to  release 
properly  when  a  tool  gets  caught  and  in  danger  of  breaking  or 
spoiling  work,  as  is  liable  to  be  the  case  on  heavy  work,  or  with  very 
heavy  cuts,  an  additional  friction  is  provided  as  safety  device,  as 
the  most  careless  operator  is  not  liable  to  screw  up  both  frictions 
beyond  the  point  of  releasing  under  an  abnormally  heavy  strain, 
in  case  of  an  accident  which  might  result  in  serious  injury  to  the 
tool,  the  work,  or  the  feeding  mechanism  in  the  apron. 

The  feed  is  positive,  by  a  series  of  gears  on  the  head-stock,  with 
the  usual  change-gears  for  operating  the  lead  screw,  which  is  splined 
for  "driving  the  apron  mechanism. 


334  MODERN  LATHE  PRACTICE 

All  sliding  surfaces  are  hand  scraped.  Taper  gibs,  with  adjust- 
ing screws,  are  used  in  the  carriage  and  compound  rest.  The  lead 
screw  is  made  of  special  steel  rolled  for  the  purpose,  2T7g  inches  in 
diameter,  and  cut  with  2  threads  per  inch.  Pinions  are  of  crucible 
steel  and  all  nuts  are  case  hardened.  The  countershaft  has  self- 
oiling  boxes.  The  weight  of  the  lathe  with  an  18-foot  bed  is  20,000 
pounds,  showing  it  to  be  a  very  massive  machine  for  its  capacity. 

Prominent  among  the  manufactures  of  heavy  lathes  is  the  Niles 
Tool  Works  who  are  also  builders  of  heavy  machine  tools  of  other 
classes  which  have  proven  very  popular  on  account  of  their  good 
design,  ample  strength,  generous  proportions  and  excellent  work- 
manship. 

In  Fig.  262  is  shown  one  of  their  72-inch  swing  lathes  adapted 


FIG.  262.  —  72-inch  Swing  Triple-Geared  Engine  Lathe,  built  by  the  Niles- 
Bement  Pond  Company  (usually  called  a  Niles  Lathe). 

for  heavy  work.  This  lathe  is  of  somewhat  similar  design  to  the 
50-inch  New  Haven  Lathe  shown  in  Fig.  261,  but  considerably 
heavier,  not  only  in  proportion  to  its  larger  swing  but  as  generally 
considered,  a  more  massive  machine. 

The  head  spindle  is  very  large  and  constructed  of  cast  iron,  as 
is  usual  with  very  large  lathes.  It  is  driven  by  means  of  the  heavy 
internal  gear  on  the  face-plate  only,  as  the  cone  runs  upon  a  separate 
shaft  provided  for  that  purpose.  The  face-plate,  which  is  very 
heavy  and  strongly  braced  by  ample  radial  ribs  on  its  rear  side,  is 
keyed  to  the  head  spindle  and  is  not  ordinarily  removable. 

The  head-stock  is  triple  geared  by  strong  and  heavy  gears  with 
wide  faces.  Thus  fifteen  speeds  are  provided  for  with  ample  space 
on  the  five-step  cone  for  a  wide  driving  belt. 

The  feeding  and  screw-cutting  mechanism  has  three  changes 


HEAVY  LATHES  335 

in  the  head-stock  by  means  of  a  sliding  pin  which  handles  the  con- 
necting devices  of  the  change  gearing.  The  lead  screw  drives  the 
feeding  mechanism  without  using  the  threads  cut  upon  it,  through 
the  medium  of  a  short  feed  rod,  located  in  the  apron.  This  method 
avoids  the  use  of  a  long  feed  rod  with  its  many  supports  and  the 
attendant  inconvenience  which  is  of  much  greater  moment  than  in 
those  used  for  the  much  larger  and  heavier  lead  screw. 

The  bed  is  very  broad  and  massive  and  furnishes  ample  support 
for  the  heavy  head-stock  and  its  weighty  appendages,  the  long  and 
broad  carriage  with  its  compound  rest  of  ample  proportion,  and 
the  massive  tail-stock,  as  well  as  for  the  four-jawed  center  rest 
which  is  furnished  with  this  lathe. 

The  tail-stock  is  broad  and  heavy  and  carries  a  large  tail  spindle, 
moved  by  a  system  of  miter  and  spur-gearing  operated  by  a  large 
hand  wheel  at  the  front  side,  and  within  convenient  reach  of  the 
operator.  The  tail-stock  is  secured  to  the  bed  by  four  heavy  bolts 
and  a  pawl  engaging  in  a  rack,  cast  to  the  bed  on  the  center  line. 

While  the  tail-stock  is  unusually  heavy  it  can  be  readily  moved 
along  the  bed  upon  friction  wheels,  which  are  easily  put  in  contact 
with  the  bed  by  means  of  levers  provided  for  that  purpose.  The 
usual  set-over  device  is  provided  for  turning  tapers. 

These  builders  make  much  larger  lathes  upon  the  same  design, 
and  also  upon  special  designs  adapted  for  making  large  guns,  ingot 
slicing,  machining  large  forgings  such  as  crank-shafts  and  the  like. 
Of  this  character  they  build  lathes  swinging  90,  100,  110,  and  120 
inches,  and  of  any  length  of  bed  that  may  be  required. 

An  excellent  example  of  heavy  lathes  for  handling  large  forg- 
ings such  as  crank-shafts  and  the  heavier  castings  coming  within 
the  capacity  of  such  a  machine  is  the  84-inch  swing  lathe,  built  by 
the  Pond  Machine  Tool  Company,  now  operating  in  connection  with 
the  Niles  Company.  It  is  shown  in  Fig.  263.  It  really  swings 
86  inches  over  the  V's  and  67  inches  over  the  carriage. 

The  lathe  is  designed  with  ample  provision  for  the  immense 
strains  to  which  such  a  lathe  is  subjected.  As  will  be  seen  by  an 
examination  of  the  engraving,  the  head-stock  is  unusually  massive, 
with  liberal  dimensions  of  the  housings  for  the  front  and  rear  boxes 
of  the  main  spindle,  which  is  a  matter  of  prime  importance  in  any 
lathe,  and  more  particularly  in  one  designed  for  very  heavy  work. 


336 


MODERN   LATHE   PRACTICE 


Attention  is  also  called  to  the  massive  construction  of  the  compound 
rest,  which  is  much  stronger  and  more  rigid  proportionally  than 
that  of  the  72-inch  swing  lathe,  built  by  the  Niles  Works  and  shown 
in  Fig.  262. 

The  carriage  has  a  very  long  bearing  on  the  bed  and  is  made 
deep  and  heavy,  as  should  be  the  case  with  this  type  of  lathe.  An 
objectionable  feature  is  that  of  locating  apron  gears  in  front  of  the 
apron  rather  than  between  the  apron  plates,  out  of  the  way  of  the 
operator  and  beyond  the  reach  of  ordinary  accidental  injury  to 
themselves.  This  should  be  avoided  as  far  as  possible  in  all  lathes. 

The  tail-stock  is  of  massive  and  rigid  design,  and  well  adapted 
for  the  heavy  work  expected  of  the  lathe.  It  is  provided  with  the 


FIG.  263.  —  82-inch  Swing  Triple-Geared  Engine  Lathe,  built  by  the  Niles- 
Bement-Pond  Company  (usually  called  a  Pond  Lathe). 

geared  device  for  moving  the  spindle,  by  which  the  hand  wheel  is 
placed  at  the  front  of  the  tail-stock  and  within  easy  reach  of  the 
operator.  The  base  is  secured  to  the  bed  by  four  bolts  in  the  usual 
manner,  while  the  dividing  line  between  the  base  and  the  top  cast- 
ing carrying  the  spindle  is  placed  high  up  and  the  top  secured  by 
four  other  bolts.  By  providing  this  double  set  of  bolts  the  spindle 
may  be  set  over  for  turning  tapers  by  loosening  the  upper  set  of 
bolts  only,  leaving  the  main  casting  or  base  still  firmly  secured  to 
the  bed.  Thus  it  is  not  necessary  to  block  up  or  to  remove  the 
work  from  the  lathe  when  setting  for  tapers,  which  is  of  considerable 
advantage,  particularly  on  the  heavy  work  which  this  lathe  is 
designed  to  do. 

In  the  builders'  description  of  this  lathe  they  say: 

"With  a  22-foot  bed,  this  lathe  will  turn  8  feet  4  inches  between 


HEAVY  LATHES  337 

centers.  All  its  spindles  are  mounted  in  bronze  bearings.  The 
head  spindle  has  upon  it  a  thick  flange  of  large  diameter  to  which 
the  face-plate  is  bolted  in  addition  to  being  forced  on.  The  cone 
has  six  wide  belt  steps  of  large  diameter.  It  is  mounted  on  the 
face-plate  pinion  shaft,  is  back  geared  and  geared  in  to  an  internal 
gear  on  the  face-plate,  giving  twenty-four  changes  of  speed.  The 
sliding  head  has  a  set-over  for  taper  turning,  held  independently 
by  four  bolts,  thus  allowing  adjustment  without  unclamping  from 
the  bed.  It  is  provided  with  a  pawl  engaging  a  rack  in  the  bed 
and  is  easily  moved  by  gearing  engaging  a  steel  rack. 

"The  bed  has  three  wide  tracks,  with  the  lead  screw  between 
them,  bringing  the  line  of  strain  nearly  central,  and  is  sufficiently 
wide  to  support  the  tool  slide  without  the  latter  overhanging  its 
front  side  when  turning  the  largest  diameters.  The  carriage  has 
long  bearings  on  the  bed,  is  gibbed  to  the  outside  edges,  and  can 
be  clamped  when  cross-feeding.  It  is  provided  with  a  tool  slide 
having  compound  and  swiveling  movements;  also  with  screw-cutting 
attachment  and  automatic  friction  longitudinal,  cross  and  angular 
feeds. 

"If  either  of  the  feeds,  screw-cutting  attachment,  or  rapid 
traverse  of  carriage  and  tool  slides  by  power  is  in  use,  it  locks  out 
all  others.  The  direction  of  the  feeds  may  be  changed  at  the  car- 
riage. Screw-cutting  attachment  and  feeds  are  connected  to  the 
head  spindle  by  three  gears  and  a  sliding  key,  giving  three  changes 
without  changing  gears.  The  carriage  gearing  is  driven  by  a  spline 
in  the  steel  lead  screw.  The  thread  of  the  lead  screw  is  used  only  for 
screw  cutting.  The  gear  engaging  the  feed  rack  can  be  disengaged 
when  cutting  screws,  thus  preventing  uneven  motion,  caused  by 
the  revolution  of  the  feed  gearing." 


CHAPTER  XVIII 

HIGH-SPEED    LATHES 

Prentice  Brothers  Company's  new  high-speed,  geared  head  lathe.  A  detailed 
description  of  its  special  features.  A  roughing  lathe  built  by  the  R.  K. 
Le  Blond  Machine  Tool  Company.  Lodge  &  Shipley's  patent  head  lathe. 
The  prime  requisities  of  a  good  lathe  head.  Description  of  the  lathe  in 
detail.  The  capacity  of  the  lathe.  A  special  turning  lathe  of  24-inch 
swing  built  by  the  F.  E.  Reed  Company.  A  two-part  head-stock.  The 
special  rest.  Its  two  methods  of  operation.  Its  special  countershaft. 
The  Lo-swing  lathe,  built  by  the  Fitchburg  Machine  Tool  Works.  Its 
peculiar  design.  A  single  purpose  machine.  An  ideal  machine  for 
small  work.  Builders  who  have  the  courage  of  their  conviction. 

THE  Prentice  Brothers  Company  have  recently  brought  out  a 
new  high-speed  geared  head  lathe,  that  possesses  some  valuable 
features  and  is  worthy  of  careful  consideration.  It  is  well  designed 
to  meet  all  the  most  rigid  demands  of  modern  shop  methods  that 
may  be  made  upon  a  lathe  of  this  character,  and  is  strongly  built  to 
withstand  all  the  shocks  and  strains  to  which  it  may  be  subjected. 

Apart  from  its  great  power,  the  machine  is  interesting  mechan- 
ically in  its  arrangement  for  procuring  eight  spindle  speeds  from  a 
single  speed  countershaft,  thus  always  furnishing  an  equal  belt 
power  no  matter  what  spindle  speed  is  in  use.  It  is  also  of  much 
interest  in  that  it  presents  a  new  modification  of  the  quick  change 
feed  device. 

The  lathe  is  shown  complete  in  Fig.  264,  and  the  details  of  the 
head-stock,  feed  gears,  and  quick  change  gear  mechanisms  in  Figs. 
265,  266,  267,  268,  269,  270,  and  271.  A  careful  study  of  these 
details  will  be  interesting  as  giving  a  clear  insight  into  the  prominent 
features  of  the  device.  As  will  be  seen  by  referring  to  Fig.  265, 
four  changes  of  speed  are  obtained  between  the  pulley  shaft  and 
the  spindle  through  an  arrangement  of  gears  and  friction  clutches, 

338 


HIGH-SPEED   LATHES 


339 


and  that  the  number  of  changes  are  doubled  by  engaging  the  back 
gears  by  means  of  a  positive  tooth  clutch. 


FIG.  264.  —  High-Speed  Engine  Lathe  built  by  the  Prentice  Bros.  Company. 

The  back  gears  never  travel  fast  enough  to  render  it  imprac- 
ticable to  use  a  positive  clutch  for  this  purpose.  The  result  is  a 
ratio  of  6  to  1  between  the  spindle  and  any  friction  while  the  back 


FIG.  265.  —  Horizontal  Section  of  Head-Stock  of 
Prentice  High-Speed  Lathe. 

gears  are  in  use.  The  driving  pulley,  which  is  located  on  a  back 
shaft,  drives  the  spindle  by  means  of  spur  gearing.  The  pulley 
carries  a  4-inch  belt,  which  runs  at  a  speed  sufficient  to  transmit 
15  horse  power. 


340 


MODERN  LATHE  PRACTICE 


The  eight  changes  of  speed  are  obtained  by  means  of  the  levers 
A,  B,  and  C,  shown  in  Figs.  266  and  267,  and  also  at  the  front  of  the 
head-stock  in  Fig.  264.  This  arrangement  of  the  several  operative 
parts  is  such  that  there  is  no  danger  of  engaging  conflicting  spindle 
speeds  at  the  same  time.  On  the  pulley  shaft  D,  in  Fig.  265,  which 
is  situated  at  the  back  of  the  head-stock,  and  revolves  at  a  constant 
speed  at  all  times,  are  two  friction  clutches  E  and  F,  either  of  which 
may  be  operated  by  the  lever  A,  which  slides  the  friction  spool  I 
along  the  shaft  D,  for  the  purpose  of  engaging  the  clutches  at  the 
right  or  the  left.  Between  the  head  spindle  and  the  pulley  shaft  D 
is  located  a  secondary  shaft  G,  which  carries  two  gears  of  different 


FIG.  266.  —  Front  Elevation  of  Head-Stock 
of  Prentice  High-Speed  Lathe. 


FIG.  267.  —  Cross  Section 
of  Head-Stock  of  Pren- 
tice High-Speed  Lathe. 


diameters,  engaging  with  corresponding  gears  upon  the  pulley  shaft 

D,  and  also  gears  which  are  fixed  to  the  hubs  of  the  friction  discs  J 
and  K.    These  friction  discs  run  loosely  upon  the  quill  L,  L,  which 
is  itself  loosely  journaled  upon  the  head  spindle  and  which  carries 
the  friction  disc  L1  at  its  end.    The  friction  rings  M,  N,  are  keyed 
to  the  quill  L.    The  friction  ring  0  is  keyed  to  the  head  spindle. 

The  four  high-speeds  are  engaged  as  follows :  With  the  frictions 

E,  M,  and  0,  driving  directly;  with  the  frictions  F,  N,  and  0,  driving 
directly;  with  the  frictions  F,  M,  and  0,  driving  through  the  inter- 
mediate shaft  G;  and  with  frictions  E,  N,  and  0,  also  through  the 
intermediate  shaft.    The  back  gears  and  the  spindle-driving  gear 
W  run  constantly,  while  the  friction  spool  I  is  engaged  with  either 
friction  E  or  F.    By  engaging  the  friction  spool  and  clutch  P,  which 
is  keyed  to  the  lathe  spindle,  with  the  spindle  driving  gear  W,  the 
back  gear  speeds  are  obtained.    If  desired,  the  lathe  is  furnished 
with  a  two-speed  countershaft,  to  double  the  number  of  speeds  to 
16. 


HIGH-SPEED   LATHES 


341 


The  device  for  changing  the  feed  and  for  the  cutting  of  screw 
threads  is  a  radical  change  from  the  swing  intermediate  gear  type, 
as  it  does  away  with  the  raising  and  lowering  an  intermediate  gear 
sweep  and  sliding  the  intermediate  gear  laterally  to  engage  with 
feed  gears  on  the  end  of  the  head  and  bed.  A  pull  spline  and  spring 
spline  in  combination  replace  the  older  mechanism. 

Upon  the  end  of  the  head-stock  and  in  the  position  usually 
occupied  by  the  regular  feed 
spindle  is  a  feed  shaft,  A,  in  Fig. 
268,  upon  which  four  gears  are 
splined.  The  shaft  is  supported 
at  its  outer  end  in  a  brass  bush- 
ing mounted  upon  the  gear  guard. 
This  shaft  with  its  gears  revolves 
at  the  same  speed  as  the  main 
head  spindle  of  the  lathe.  Below 
the  feed  shaft  is  a  hollow  stud  B, 
on  which  are  loosely  mounted 
four  gears  meshing  with  the  feed 

gears  on  A.     The  gears   on   both     FIG.  268.  —  Vertical  Section  of  Feed 

.,!     ,-,  Gears  of  Prentice  High-Speed  Lathe. 

A  and  B  run  constantly  with  the 

main  spindle  when  not  disengaged  by  the  usual  rocker  device  on 
the  end  of  the  head-stock  at  0. 

The  two  groups  of  gears  are  of  the  ratio  2  to  1, 1  to  1, 1  to  2,  and 

1  to  4,  which,  in  connection  with  the  bank  of  gears  mounted  on  the 

side  of  the  head,  gives  a  range  of  thread  cutting  from  2  to  32  per 

inch.  The  feed  cuts  per  inch  are  5.7  times  the  number  of  threads  cut. 

The  hollow  stud  B  contains  a  pull  rod,  C,  which  has  fastened  to 

its  end  the  spring  spline  D.  The 
spring  spline  allows  changes  of 
feed  and  thread  cutting  to  be 
made  instantly  while  the  lathe  is 
in  motion,  by  sliding  the  handle 

FIG.  269.  —  Change-Gear  Levers  of        E,  Fig.  269,  on  its  guide  rod,  the 
Prentice  High-Speed  Lathe.  handle  projecting  from  the   side 

of  the  head-stock  and  connected  with  pull  rod  C,  at  F,  in  Fig.  268. 
The  hollow  shaft  B  contains  a  slot  running  the  full  width  of  the 
four  gears. 


342 


MODERN  LATHE  PRACTICE 


When  it  is  desired  to  change  the  rate  of  feed,  the  pull  spline  C 
being  moved  laterally  causes  the  spring  spline  to  be  withdrawn 
from  a  slot  in  the  bushing  on  the  feed  gear,  throwing  that  gear  out 
of  use.  When  the  spring  spline  passes  the  pin  E  it  immediately 
engages  the  next  gear.  The  form  of  the  driving  end  of  the  spline 
makes  this  action  against  the  pins  possible. 

The  gears  G,  G,  in  Fig.  268,  drive  the  gear  H  in  Fig.  270,  which  is 

fastened  to  the  shaft  J,  on  which 
is  mounted  a  yoke  carrying  a  slid- 
ing intermediate  gear,  which  en- 
gages with  the  several  gears 
mounted  on  shaft  K.  There  being 
11  gears  in  this  bank,  44  changes  of 
feed  are  obtained.  Sliding  on  the 
end  of  shaft  K  in  Fig.  270  is  the 
gear  L,  which  by  means  of  a  han- 
dle on  the  front  of  the  bed  may  be 
engaged  with  either  gear  M  on  the 
feed  rod  or  gear  N  on  the  lead 
FIG.  270.  —  End  Elevation  of  Gear-  screw.  This  device  is  intended 
ConnectionsofPrenticeHigh-Speed  especially  to  preserve  the  lead 

screw  for  screw-cutting  purposes, 

as  a  great  deal  of  care  is  taken  in  the  manufacture  of  these  screws 
to  have  them  accurate. 

The  diagram  shown  in  Fig.  271  is  of  an  end  view  of  the  head- 


FIG.  271.  —  Diagram  of  Gear  Connections  of  Prentice 
High-Speed  Lathe. 

stock,  showing  the  gear  connections  from  the  head  spindle  to  the 
cone  of  gears  shown  in  section  in  Fig.  270,  and  is  useful  and  inter- 


HIGH-SPEED   LATHES 


343 


esting  in  tracing  the  line  of  motion  produced  by  these  gears.  The 
entire  scheme  of  the  head-stock  and  its  operative  parts  is  ingenious 
and  a  well-devised  piece  of  mechanism. 

A  roughing  lathe,  built  by  the  R.  K.  Le  Blond  Machine  Tool 
Company,  is  shown  in  Fig.  272,  and  is  principally  interesting  from  the 
strength  of  its  parts  in  proportion  to  the  dimensions  of  the  work  that 
it  will  accommodate.  This  lathe  is  built  of  18, 21  and  24-inch  swing, 
and  has  an  extra  large  spindle  which  runs  in  genuine  babbitt  metal 
bearings. 

The  carriage  is  much  heavier  than  an  ordinary  engine  lathe,  and 
is  extended  out  both  back  and  front  for  additional  bearing  for  tool 
rests.  Of  these  there  are  two,  one  in  front  and  the  other  at  the 


u 


FIG.  272.  —  18-inch  Swing  Roughing  Lathe  built  by  the  R.  K.  Le  Blond 

Machine  Tool  Company. 

rear.  The  front  tool  rest  has  an  extra  movement  in  line  with  the 
slide.  The  back  tool  rest  has  an  extra  movement  at  right  angles  to 
the  slide.  Both  of  these  are  moved  by  a  single  screw  moving 
towards  or  away  from  the  center  together. 

The  tail-stock  is  fastened  to  the  bed  with  four  large  bolts,  clamp- 
ing it  as  far  forward  as  possible.  The  feed  is  positive  geared  and  is 
changed  by  means  of  lever  shown  in  front  of  the  bed,  giving  three 
changes,  and  can  be  stopped  automatically  at  any  point  desired. 
By  tripping  it  with  a  small  handle  on  the  front  of  the  apron  the 
carriage  will  proceed  without  removing  the  stop,  and  keep  on  until 
it  comes  in  contact  with  the  next  stop. 

The  lathe  is  fitted  with  a  geared  oil  pump  for  a  continuous  flow 


344  MODERN  LATHE   PRACTICE 

of  oil  on  the  work;  the  pan  is  large  enough  to  keep  all  dirt,  oil,  and 
chips  from  the  floor.  Countershaft  has  double  friction  pulleys. 

This  lathe  is  intended  for  heavy  and  rough  work,  as,  for  instance, 
rough  turning  forgings  and  heavy  pieces  of  cut-off  work  that  re- 
quires to  be  largely  reduced  in  diameter  with  a  heavy  roughing 
cut.  With  the  present  low  price  of  machine  steel  there  is  a  good 
deal  of  the  latter  class  of  work  to  be  done,  and  it  can  be  done  much 
more  quickly  and  economically  in  a  lathe  of  the  class  here  shown 
than  in  the  usual  engine  lathe,  and  its  use  saves  the  unnecessary 
wear  when  such  work  is  done  on  the  more  expensive  lathe. 

Therefore  the  heavy  roughing  lathe  is  not  only  a  saving  in  time 
and  in  money  for  doing  the  work,  but  also  of  the  cost  of  tool  equip- 
ment. 

It  was  this  idea  that  induced  the  design  and  construction  of 
the  so-called  " rapid  reduction  lathes,"  which  have  come  to  be 
popular  with  manufacturers,  not  only  on  account  of  their  economical 
expenses,  but  high  efficiency. 

Turret  lathes  are  sometimes  used  in  a  similar  manner,  cutting 
off  and  roughing  out  the  pieces  from  the  bar  stock,  and  are  very 
efficient  in  doing  this  class  of  work.  The  first  cost  of  these  ma- 
chines, however,  is  much  more  than  that  of  the  plain  roughing 
lathe. 

The  Lodge  &  Shipley  Machine  Tool  Company  build  a  lathe  with 
a  head-stock  that  is  a  radical  departure  from  the  usual  form  of 
cone-driven  lathes  and  which  is  entitled  to  special  consideration.  It 
is  the  result  of  much  experimenting  and  is  covered  by  patents. 
Commercially  they  call  it  their  "  Patent  Head  Lathe."  It  is  an 
outcome  of  the  recognition  by  the  builders  of  tha  demand  for  a 
much  more  powerfully  driven  lathe  for  the  use  of  modern  high- 
speed lathe  tools. 

The  manufacturer  of  the  lathe  says:  "Our  aim  in  its  design  has 
been  to  provide  this  power  in  such  a  manner  that  all  the  functions 
of  the  regular  type  would  be  retained,  but  the  head  would  have 
wearing  qualities,  in  addition,  proportionate  to  the  increased  service 
expected  of  it.  To  this  end  we  believe  the  observance  of  the  follow- 
ing conditions  to  be  of  the  highest  importance :  First,  the  spindle 
bearings,  upon  which  the  accuracy  of  the  lathe  is  dependent,  should 
not  be  subjected  to  the  change  of  alignment  by  carrying  the  pull 


HIGH-SPEED   LATHES 


345 


of  the  belt.  Second,  more  force  at  the  cutting  tool  should  be 
secured  by  the  use  of  wider  belts,  instead  of  through  higher  gear 
ratios.  Third,  the  possibility  of  running  the  lathe  'out  of  gear' 
should  be  provided  for  in  cases  where  finishing  cuts  are  desired. 
Fourth,  speed  changes  should  be  secured  without  the  necessity  of 
shifting  belts.  Fifth,  the  lubrication  of  the  bearings  should  be 
automatic  and  positive." 

Doubtless  every  thoughtful  mechanic  will  readily  assent  to 
these  propositions  as  being  self-evident. 

Figure  273  shows  the  head-stock  in  place  upon  the  bed  and 


FIG.  273.  —  Head-Stock  for  Lodge  &  Shipley  Patent  Head  Lathe. 


with  the  main  spindle  and  the  gear  covers  removed  in  order  to 
show  the  construction  of  the  driving  mechanism.  Power  is  applied 
through  a  wide-faced  pulley  of  large  diameter  which  is  keyed  to  a 
sleeve  revolving  in  the  two  central  bearings  of  the  head-stock.  At 
one  end  of  this  sleeve  is  a  jaw  clutch,  and  at  the  opposite  end  two 
gears  of  different  diameters.  The  main  spindle  passes  through  this 
sleeve  without  coming  in  contact  with  it,  having  about  an  eighth  of  an 
inch  clearance,  and  revolves  in  the  two  outer  bearings,  that  is,  the 
extreme  front  and  the  extreme  rear  bearing.  It  is  connected  to  the 


346  MODERN  LATHE  PRACTICE 

driving  sleeve  for  direct  belt  speeds  by  the  clutch,  and  for  the  back 
gear  speeds  through  either  back  gear,  according  to  the  speed 
desired.  A  lever,  convenient  for  the  operator,  engages  or  dis- 
engages the  clutch. 

As  there  is  no  contact  between  the  driving  sleeve  and  the  spindle 
except  through  the  clutch,  the  pull  of  the  belt  is  all  carried  by  the 
two  central  bearings.  Sufficient  clearance  is  provided  in  the  clutch 
to  prevent  any  of  the  belt  strain  being  communicated  through  it 
to  the  spindle.  The  spindle  bearings  are  thus  relieved  of  all  wear 
due  to  belt  pull  and  their  life  greatly  prolonged.  By  actual  experi- 
ment with  a  20-inch  lathe  it  has  been  shown  that  the  pressure 
exerted  by  a  belt  on  spindle  bearings  was  17.6  pounds  per  square 
inch  of  bearing  surface,  while  the  total  pressure  exerted  by  the  belt 
upon  a  spindle  between  bearings  which  effect  the  alignment  of  the 
spindle  was  393  pounds.  In  the  lathe  under  consideration  this  was 
entirely  eliminated. 

In  the  ordinary  type  of  engine  lathe  the  narrowness  of  the 
driving  belt  compels  the  use  of  the  back  gears  for  all  cuts  but  the 
lightest  ones,  and  on  small  diameters.  To  provide  sufficient  force 
at  the  tool  for  heavy  cuts,  this  back  gear  ratio  must  necessarily  be 
a  high  one,  and,  as  the  speed  at  which  the  cut  is  taken  is  reduced 
in  the  same  ratio  as  force  is  gained,  it  is  apparent  that  a  heavy  chip 
cannot  be  removed  at  a  high  speed  unless  the  speed  of  the  cone 
pulley  is  increased  to  an  enormous  rate.  When  this  is  done,  the 
fact  that  it  revolves  directly  on  the  spindle,  where  it  is  imprac- 
ticable to  maintain  an  adequate  supply  of  oil,  soon  causes  excessive 
friction  and  is  liable  to  stick  the  cone  pulley. 

In  the  lathe  we  are  considering  the  great  width  of  belt  used 
delivers  sufficient  force  at  the  cutting-tool  for  heavy  cuts  through  a 
comparatively  low  back  gear  ratio,  in  consequence  of  which  the 
spindle  speeds  may  be  proportionately  higher.  An  additional  set 
of  back  gears  of  very  low  ratio  is  provided  for  cuts  which  are  slightly 
beyond  the  capacity  of  the  open  belt,  but  which  do  not  require  the 
full  force  afforded  by  the  high  ratio.  Thus  it  will  be  seen  that  high 
speeds  can  be  secured  through  the  back  gears  without  the  neces- 
sity of  revolving  the  driving  pulley  at  the  enormous  rate  required 
of  a  cone  pulley  to  perform  the  same  work.  In  addition  the  con- 
struction of  its  bearings  is  such  as  to  permit  of  perfect  lubrication, 


HIGH-SPEED   LATHES  347 

which  has  received  a  great  deal  of  attention,  and  the  manufacturers 
claim  that  the  spindle  will  run  a  month  with  one  oiling.  Deep  oil 
wells,  holding  about  a  pint  each,  are  formed  in  the  casting  under 
the  centers  of  the  bearings  of  the  spindle  and  driver  sleeve,  and 
are  connected  with  gage  glasses  at  the  front  of  the  head-stock  for 
the  purpose  of  showing  the  height  of  the  oil.  The  oil  wells  are  filled 
through  these  gage  glasses,  which  allows  any  sediment  or  dirt 
which  the  oil  may  contain  to  settle  to  the  bottom  and  not  be  de- 
posited on  the  revolving  journals  where  damage  would  be  liable 
from  cutting.  At  the  center  of  each  journal  is  attached  a  brass 
ring  with  four  projections,  on  the  principle  of  the  bucket  pump. 
As  the  journal  revolves  these  buckets  dip  into  the  oil  in  the  well, 
and,  passing  over  the  center  of  the  bearing,  pour  the  oil  over  the 
journal.  Suitable  ducts  distribute  the  oil  lengthwise  of  the  bear- 
ing and  return  it  to  the  well  to  be  used  again  and  again.  This 
method  provides  a  certain  system  of  lubrication  without  regard  to 
the  speed  of  the  revolving  spindle. 

The  back  gearing  is  designed  with  ratios  to  give  a  uniform  pro- 
gression of  speed  from  the  slowest  to  the  fastest.  The  two  back 
gears  are  connected  to  the  back  gear  shaft  by  spline  and  key,  and 
are  easily  moved  lengthwise  to  engage  with  their  respective  gears 
on  the  driving  sleeve.  The  back  gear  shaft  and  pinion  are  made  of 
forged  steel,  thus  insuring  the  requisite  strength  and  wearing  qual- 
ities. The  journals  for  the  shaft  are  placed  at  either  end,  where 
they  revolve  in  bushings  provided  with  oil  reservoirs  and  the  same 
system  of  oiling  as  that  for  the  spindle  and  driving  sleeve. 

The  end  thrust  of  the  spindle  is  against  the  rear  housing  of  the 
head-stock  by  means  of  a  large  cast  iron  collar  keyed  fast  to  the 
spindle,  between  which  and  the  faced  inside  of  the  housing  are 
interposed  two  bronze  washers  placed  on  either  side  of  a  hardened 
steel  washer  of  like  diameter.  This  distributes  the  friction  to  four 
contacts,  each  composed  of  two  dissimilar  metals,  and  forming  a  very 
efficient  device  for  the  purpose. 

A  variable  speed  countershaft  is  provided  for  the  lathe,  by  which 
a  wide  range  of  speeds  may  be  obtained. 

In  Fig.  274  is  shown  a  front  elevation  of  this  lathe  with  the 
gear  covers  removed  so  as  to  show  the  head-stock  assembled  and 
in  running  condition.  The  gear  covers  are  of  cast  iron  and  cover 


348 


MODERN  LATHE  PRACTICE 


and  protect  all  portions  of  the  head-stock  mechanism,  except  the 
wide-faced  driving  pulley.  This  will  show  the  relative  importance 
which  a  head-stock  built  according  to  this  system  holds  to  the  other 
constituent  parts  of  the  machine.  It  also  shows  the  very  consider- 
able added  length  necessary  for  the  head-stock,  and  therefore  the 
reduced  length  between  centers  when  the  same  length  of  bed  is 
considered. 

But  while  the  capacity  of  the  lathe,  so  far  as  length  between 
centers  is  concerned,  is  relatively  much  less,  the  real  capacity  of 
the  lathe  for  producing  work,  good  work,  is  so  vastly  increased  that 
the  production  of  this  head  may  fairly  be  considered  as  adding 


FIG.  274.  —  22-inch  Swing  Patent  Head  Lathe,  built  by  the  Lodge  & 
Shipley  Machine  Tool  Company. 

very  much  to  the  development  of  the  lathe  as  a  modern  American 
machine  shop  tool. 

A  24-inch  special  turning  lathe  is  built  by  the  F.  E.  Reed  Com- 
pany that  is  designed  for  reducing  large  amounts  of  metal  at  one 
turning,  using  the  high-speed  steel  tools,  and  is  an  unusually  stiff, 
strong,  and  powerful  machine. 

The  head-stock  is  made  in  two  parts  to  admit  of  a  cone  pulley  as 
large  as  the  lathe  will  swing  over  the  bed.  It  has  a  large,  forged 
steel  spindle,  the  front  bearing  of  which  is  4J  inches  diameter  by 
9}  inches  long,  and  runs  in  babbitt  lined  bearings.  The  spindle  is 
strongly  back  geared.  The  cone  pulley  has  five  sections,  the  largest 
of  which  is  20 J  inches  diameter,  driven  by  a  3i-inch  belt;  then  with 
the  two  friction  pulleys  on  the  countershaft  this  number  of  speeds 
can  be  doubled,  making  a  total  of  twenty  speeds  which  can  be  had 


HIGH-SPEED   LATHES  349 

if  desired.  This  lathe  can  be  furnished  with  four-step  cone  for  wider 
belt  if  desired. 

A  special  feature  of  this  lathe  is  the  rest.  It  is  provided  with 
two  patented  elevating  tool-posts,  each  having  a  universal  tool- 
holder,  in  which  any  size  of  steel  can  be  used  to  advantage,  and  so 
made  that  they  admit  of  adjustment  up  and  down  while  the  tool 
is  under  cut.  Each  tool-post  is  moved  from  the  front  by  a  separate 
screw,  and  the  rear  tool-post  is  provided  with  a  screw  for  adjust- 
ment crosswise  of  the  rest.  These  tools  can  both  be  used  to  turn 
to  the  same  diameter  by  dividing  the  chip;  or,  they  can  be  used  to 
reduce  the  diameter,  removing  large  amounts  of  stock,  working  one 
tool  in  advance  of  the  other,  each  tool  turning  to  a  different  diameter. 

A  positive  geared  feed  is  provided,  and  so  arranged  that  either  a 
fine  or  a  coarse  feed  can  be  obtained  by  means  of  the  lever  shown 
at  the  front  of  the  lathe. 

There  are  two  methods  of  operation : 

First.  When  it  is  desired  to  do  rapid  turning,  and  where  it  is 
not  necessary  to  largely  reduce  the  diameter,  the  front  tool  is 
brought  up  to  the  work  and  set  so  it  will  reduce  the  piece  to  the 
required  diameter.  Then  the  rear  tool  is  adjusted  to  a  point  where 
it  will  turn  to  the  same  diameter  as  the  front  tool,  after  which  it  is 
adjusted  by  means  of  the  cross  adjusting  screw  so  that  it  will  divide 
the  chip.  Then  by  means  of  the  small  lever  shown  at  front  of 
lathe  a  coarser  feed  is  engaged. 

Second.  When  large  reductions  in  diameter  are  desired,  the 
front  tool  can  be  set  to  remove  the  required  amount  of  stock, 
and  the  rear  tool  set  to  follow  the  front  tool  for  removing  a  second 
large  chip  from  a  different  or  smaller  diameter. 

Arranged  for  either  of  the  foregoing  operations  the  lathe  will 
turn  off  twice  the  amount  of  stock  that  can  be  removed  at  one 
turning  in  the  ordinary  24-inch  engine  lathe,  using  the  high-speed 
turning  steels. 

This  lathe  is  set  up  with  a  pan  and  is  provided  with  a  pump  and 
piping  for  ample  lubrication  of  the  cut  ting- tools. 

The  countershaft  is  furnished  with  two  patent  friction  pulleys  for 
two  speeds,  200  and  250  revolutions  per  minute.  These  pulleys 
are  18  inches  diameter  and  take  a  5-inch  belt.  The  pulleys  are  so 
arranged  that  they  can  be  oiled  while  running,  thereby  saving  loss  of 


350 


MODERN   LATHE   PRACTICE 


time,  danger,  and  annoyance  in  running  off  the  belts,  which  is  an 
important  consideration  where  a  number  of  lathes  are  in  use.  The 
countershaft  is  also  furnished  with  self-oiling  boxes. 

This  lathe  is  shown  in  Fig.  275,  wherein  its  ample  proportions 
and  excellent  design  may  be  seen  and  appreciated.  It  is  undoubt- 
edly one  of  the  best  lathes  of  its  kind,  and  for  this  particular  and 
important  use,  now  on  the  market.  With  a  10-foot  bed  this  lathe 
weighs  7,390  pounds. 


FIG.  275.  —  24-inch  Swing  Special  Turning  Lathe,  built  by  the 
F.  E.  Reed  Company. 

A  special  lathe  has  been  brought  out  by  the  Fitchburg  Machine 
Works  at  a  comparatively  recent  date  that  is  unique  in  construction 
in  a  number  of  ways,  and  for  these  reasons,  as  well  as  for  its  claim 
to  a  large  production  of  work  within  a  limited  range,  it  is  worthy  of 
considerable  attention. 

It  is  called  the  "Lo-swing"  lathe,  and  has  a  capacity  from  J  to 
3}  inches  in  diameter  and  up  to  5  feet  in  length.  The  builders  say: 
"We  have  purposely  limited  the  range  of  work  handled  in  order 
to  increase  productive  capacity  —  a  Lo-swing  will  do  from  three 
to  four  times  as  much  work  as  an  ordinary  lathe  in  the  same  time. 

"The  extremely  low  swing  and  the  single  slide  tool  carriages, 
all  four  of  which  can  be  employed  simultaneously,  are  distinguish- 
ing features  of  this  machine,  and  the  greater  driving  power,  greater 
stability,  the  accurate  control  of  tools  and  work,  made  possible 
by  this  construction,  result  in  such  rapid  and  economical  produc- 
tion of  work  that  the  Lo-swing  is  already  an  acknowledged  cost- 
reducer  for  the  shop. 


HIGH-SPEED   LATHES 


351 


"  The  greater  driving  power,  greater  stability,  the  accurate  con- 
trol of  tools  and  work,  the  low  swing  and  small  carriages,  made 
possible  by  thus  limiting  the  range,  result  in  such  rapid  and  eco- 
nomical production  of  work  that  the  Lo-swing  stands  in  the  front 
rank  as  a  cost  reducer." 

Figure  276  is  a  perspective  view  of  this  lathe,  and  gives  a  good 
idea  of  its  general  appearance.  The  aim  of  the  builders  is  to  so 
design  the  lathe  as  to  limit  its  range  of  work  so  narrow  as  to  make 
it  "a  single  purpose"  machine,  that  is,  to  confine  its  operations  to 
one  single  class  of  work  and  then  produce  as  much  of  that  one  class 
as  possible. 


FIG.  276.  —  The  "Lo-Swing"  Lathe,  built  by  the  Fitchburg 
Machine  Works. 

Its  two  distinctive  features  are  first,  its  very  low  swing,  just 
enough  to  clear  a  3J-inch  bar;  and  second,  single  tool  slide  carriages, 
several  of  which  may  be  simultaneously  employed. 

Tfae  ideal  machine  for  turning  small  work,  which  must  be  turned 
on  centers,  should  have  the  tool  mounted  on  a  low  rest  with  the 
guiding  rail  as  close  to  the  work  as  possible,  and  with  the  cross-feed 
screw  located  directly  back  of  the  cutting-tool  so  that  a  change  of 
the  screw  would  surely  and  positively  effect  a  corresponding  change 
in  the  position  of  the  tool, .and  so  that  variation  under  working 


352  MODERN  LATHE  PRACTICE 

strain  from  no  load  at  all  to  a  full  load,  or  from  a  very  light  chip 
to  a  very  heavy  one,  would  have  the  least  possible  effect  on  the  loca- 
tion of  the  tool. 

While  these  conditions  have  been  presented,  time  out  of  mind, 
by  the  mechanical  engineers  who  have  studied  the  lathe  question 
and  its  relation  to  the  regular  lathes  built  and  put  on  the  market, 
the  lathe  builders  have  been  slow  to  adopt  such  radical  changes  as 
would  properly  accomplish  the  required  result. 

The  builders  of  the  Lo-swing  lathe  have  cut  loose  from  the  con- 
servative methods  of  other  lathe  builders  in  producing  this  machine. 

While  it  is  yet  too  early  to  determine  what  will  be  the  success 
of  this  venture,  and  how  popular  it  may  become  with  manufacturers 
requiring  such  a  machine,  it  seems  at  this  writing  to  have  a  bright 
future  before  it  as  a  practical  manufacturing  machine,  and  its  builders 
are  certainly  entitled  to  considerable  credit  for  having  the  courage 
of  their  convictions  in  bringing  it  out. 


CHAPTER  XIX 

SPECIAL   LATHES 

The  F.  E.  Reed  turret-head  chucking  lathe.  Its  special  features.  A  useful 
turning  rest.  The  Springfield  Machine  Tool  Company's  shaft-turning 
lathe.  The  three-tool  shafting  rest.  The  driving  mechanism,  Lubrica- 
tion of  the  work.  The  principal  dimensions.  Fay  &  Scott's  extension 
gap  lathe.  Details  of  its  design.  McCabe's  double-spindle  lathe.  Its 
general  features.  Its  various  sizes.  Pulley-turning  lathe  built  by  the 
New  Haven  Manufacturing  Company.  A  special  crowning  device.  Its 
general  design.  A  defect  in  design.  The  omission  of  a  valuable 
feature.  Pulley-turning  lathe  built  by  the  Niles  Tool  Works.  A  pulley- 
turning  machine.  Its  general  construction.  Turning  angular  work.  Con- 
venience of  a  bench  lathe.  The  Waltham  Machine  Company's  bench 
lathe.  Its  general  dimensions  and  special  features.  A  grinding  and  a 
milling  machine  attachment.  Devising  special  attachments.  Reed's 
10-inch  swing  wood-turning  lathe.  Special  features  of  design.  Popu- 
larity and  endurance.  The  countershaft.  Inverted  Vs. 

THE  F.  E.  Reed  Company  build  a  number  of  sizes  of  turret 
head  chucking  lathes,  with  both  plain  and  back-geared  head- 
stocks,  and  cylindrical  turrets  placed  upon  a  lateral  top  slide  sup- 
ported by  a  heavy  base  or  bottom  slide  fitted  to  the  V's  of  the  bed. 

In  Fig.  277  is  shown  one  of  these  lathes  with  a  back-geared 
head-stock.  The  spindle,  which  is  of  crucible  steel,  is  bored  out  to  2 
inches  and  has  a  front  bearing  4  inches  in  diameter.  It  is  fitted 
with  a  three-step  cone,  the  diameters  of  which  are  7f ,  11,  and  14 
inches  and  carries  a  3J-inch  belt. 

The  turret  is  12  inches  in  diameter  and  has  four  holes,  2  inches 
diameter.  It  is  arranged  to  be  turned  by  hand,  although,  of  course, 
may  be  made  automatic  in  its  action  if  desired.  The  turret  slide 
is  38  inches  long  and  has  a  movement  of  17  inches,  with  an  auto- 
matic feed  and  stop  device.  The  turret  shoe  or  bottom  sli^e  is 
26  inches  long. 

353 


354 


MODERN   LATHE   PRACTICE 


The  patented  rest  is  a  special  feature.  It  is  hinged  to  a  slide 
which  is  bolted  to  the  back  side  of  bed,  and  adjustable  for  any 
length  of  work.  It  carries  bushing  for  holding  chuck  drills,  and  is 
arranged  to  be  turned  back  out  of  the  way  instantly  to  allow  the  use 
of  other  tools  in  the  turret.  This  is  a  strong,  powerful  lathe,  and 
with  the  Guilders  system  of  three-lip  drills  and  reamers,  fully  one 
third  more  holes  can  be  made  than  with  ordinary  turret  chuck 
lathes. 

The  lathe  is  built  heavy  and  strong  and  the  parts  are  well  fitted 
and  of  good  material,  so  as  to  stand  the  hard  and  continuous  service 
to  which  such  a  machine  is  subjected,  as  well  as  the  neglect  and  the 


FIG.  277.  —  20-inch  Swing  Turret  Head  Chucking  Lathe,  built  by  the 

F.  E.  Reed  Company. 

dirt  and  sand  incidental  to  chucking  work  on  rough  castings.  With 
a  7J-foot  bed  the  lathe  weighs  2,750  pounds. 

The  turning  of  shafting  requires  not  only  a  specially  designed 
tool  carriage,  carrying  three  tools,  but  there  should  be  a  special 
arrangement  of  the  feeding  mechanism,  specially  long  centers,  and 
special  devices  for  supporting  the  long  shafts  near  the  cutting-tools 
as  they  are  being  turned.  These  conditions  have  been  considered 
and  provided  for  in  the  24-inch  swing  shafting  lathe,  built  by  the 
Springfield  Machine  Tool  Company,  which  is  shown  in  Fig.  278. 

The  three-tool  shafting  rest  takes  the  place  of  the  usual  com- 
pound rest,  and  when  in  place  connects  the  gear  upon  its  oil  pump 


SPECIAL   LATHES 


355 


shaft  to  a  similar  gear  on  the  driving  shaft  running  the  entire  length 
of  the  bed.  In  designing  the  three- tool  rest,  two  of  the  tools  are 
placed  on  the  left  and  one  tool  on  the  right  of  a  massive  follow  rest. 
All  of  these  tools  are  on  the  front  side  of  the  shaft  to  be  turned,  in 
which  position  they  are  convenient  to  manipulate  and  their  cutting 
edges  are  always  in  plain  sight.  Some  builders  put  one  of  these 
tools  in  a  reversed  position  in  the  rear  of  the  shaft,  to  be  turned  so 
as  to  balance  the  cutting  strains  better. 

There  is  a  driving  mechanism  arranged  at  the  tail-stock  as  well 
as  the  head-stock,  which  is  very  convenient  when  turning  shafts 
very  long  in  proportion  to  their  diameter,  and  hence  subject  to 
unusual  torsional  strains.  Either  of  these  drives  may  be  thrown 
into  gear  instantly,  Thus  in  turning  a  long,  slim  shaft,  that  half 


FIG.  278.  —  24-inch  Swing  Shaft  Turning  Lathe,  built  by  the  Springfield 

Machine  Tool  Company. 

near  the  tail-stock  may  be  turned  with  the  tail-stock  driving 
mechanism.  As  the  tools  pass  the  center  of  the  shaft  the  tail- 
stock  drive  is  thrown  out  of  gear  and  the  head-stock  drive  engaged, 
The  saving  of  time  by  having  the  drive  applied  near  the  point  of 
resistance  to  the  cutting  tools  should  be  considerable  on  long  work. 

Attention  is  called  to  the  substantial  manner  in  which  the  tail- 
stock  spindle  is  clamped  in  order  to  render  it  suitable  for  support- 
ing the  driving  mechanism,  and  also  for  furnishing  a  large  wearing 
surface  for  the  supplemental  face-plate  and  face  gear  upon  the 
body  of  the  tail-stock. 

The  method  used  for  guiding  the  shaft  in  the  follow  rest  is  to 
pass  it  through  a  split  cylindrical  collar,  one  of  which  is  furnished 
for  each  diameter  of  shaft  to  be  turned.  These  collars  are  broad 


356  MODERN   LATHE  PRACTICE 

enough  to  furnish  sufficient  bearing  surface  to  the  shaft  to  prevent 
undue  friction  or  cutting,  while  they  hold  the  shaft  accurately  in 
place  and  can  be  closed  up  with  an  adjusting  screw  to  compensate 
for  any  wear  that  may  occur  by  continued  use. 

As  a  copious  supply  of  lubricant  is  essential  in  shaft  turning, 
a  duplex  single-acting  plunger  force  pump  is  bolted  under  the  water 
reservoir  of  the  shafting  rest,  from  which  it  receives  its  supply. 
Water  is  forced  up  into  a  tank  sufficiently  elevated  to  bring  the 
supply  tubes  to  the  proper  height  above  the  cutting- tools.  This 
tank  is  arranged  with  an  automatic  relief  valve  susceptible  of  adjust- 
ment so  that  any  desired  pressure  can  be  obtained.  By  this 
arrangement  the  operator  need  not  give  any  attention  to  the  pump 
when  he  starts  up  the  lathe,  inasmuch  as  it  provides  auto- 
matically for  the  overflow  should  no  water  be  required.  The  water 
used  may  have  added  to  it  soda,  soap,  or  any  of  the  usual  ingredients 
used  for  such  purposes. 

On  this  lathe,  when  arranged  as  above,  it  is  only  necessary  to 
remove  the  shafting  rest,  replace  the  compound  rest,  disconnect 
the  tumbler  gear  under  the  head-stock,  and  the  lathe  is  ready  to 
perform  any  of  the  ordinary  functions  of  an  engine  lathe,  thus 
making  it  a  valuable  convertible  lathe  where  there  is  not  shaft-turn- 
ing work  to  keep  it  going  all  the  time,  although  that  is  the  primary 
object  in  designing  it  and  that  is  supposed  to  be  its  chief  function. 

The  long  centers  shown  are  necessary  as  they  must  reach  through 
the  bushing  in  the  shafting  rest,  which  is  mainly  depended  upon  to 
support  the  shaft  during  the  process  of  turning.  They  are  bored 
and  reamed  to  the  diameter  which  the  shaft  is  turned  by  the  second 
tool  (the  first  tool  being  a  roughing  tool),  and  then  split  so  that  by 
a  little  compression,  exerted  by  a  set  screw  provided  for  that  pur- 
pose, the  bushing  is  held  in  position  and  the  shaft  is  accurately 
supported  in  its  proper  place. 

Some  of  the  principal  dimensions  of  this  lathe  are  as  follows: 
Front  bearing  of  main  spindle,  4  inches  in  diameter  and  7  inches 
long.  Hole  through  the  spindle,  1J  inches.  The  driving  cone  has 
five  steps,  the  largest  of  which  is  16  inches  in  diameter  and  adapted 
for  a  3J-inch  belt.  The  ratio  of  the  back  gearing  is  12  to  1.  The 
feeds  are  from  4  to  65  per  inch.  The  lathe  turns  shafting  up  to 
5  inches  in  diameter.  Five  feet  of  the  length  of  the  bed  is  occupied 


SPECIAL  LATHES 


357 


by  the  head-stock  and  tail-stock.  The  tail-stock  spindle  is  2} 
inches  in  diameter  and  has  a  travel  of  9  inches. 

This  lathe  with  a  35-foot  bed  (to  take  30  feet  between  centers) 
weighs,  13,000,  pounds,  showing  its  substantial  construction  and 
ability  to  handle  heavy  shafting  successfully. 

Fay  &  Scott  are  the  builders  of  an  extension  gap  lathe  which 
has  the  advantage  over  a  lathe  whose  bed  is  cast  with  a  fixed  dis- 
tance in  the  width  of  the  gap,  as  shown  in  Fig.  23.  In  this  case  there 
is  a  base  or  lower  bed,  as  shown  in  Fig.  279,  upon  which  the  bed 
proper,  or  upper  portion,  is  mounted  and  upon  which  it  slides. 


FIG.  279.  —  The  Fay  &  Scott  Extension  Gap  Lathe. 

By  this  arrangement  the  "gap"  can  be  widened  to  any  distance 
desired,  or  it  can  be  closed  up  entirely,  converting  it  into  an  ordi- 
nary lathe.  This  is  a  great  convenience  on  heavy  work,  particularly 
in  a  jobbing  shop,  or  in  any  shop  where  there  is  a  great  variety  of 
work  to  be  done  upon  which  large  diameters  occur,  as  the  fly-wheels 
on  crank  shafts,  large  pulleys,  and  similar  work. 

The  lathe  is  triple  geared  direct  to  the  face-plate,  the  triple  gear 
ratio  being  34  to  1.  The  carriage  is  extended  for  turning  work 
the  full  swing  of  the  lathe,  and  is  supported  by  an  angle  bracket 
with  an  adjustable  gib  on  the  lower  bed.  The  lathe  swings  over 
the  bed  28  inches,  and  through  the  gap  52  inches. 

The  12-foot  lathe  takes  6J  feet  between  centers  when  closed, 
and  10 J  feet  when  extended.  The  gap  opens  4  feet,  and  every 
additional  foot  of  bed  lengthens  the  gap  6  inches. 

Whatever  may  be  the  opinion  as  to  the  advisability  of  building 


358 


MODERN   LATHE   PRACTICE 


a  lathe  with  two  spindles  for  th&  purpose  of  furnishing  a  lathe  of 
large  and  small  capacity,  the  fact  still  remains  that  the  two-spindle 
lathe,  brought  out  a  number  of  years  ago  by  J.  J.  McCabe,  has 
achieved  a  notable  commercial  success  and  many  of  them  are  in 
use. 

An  illustration  of  the  26-48  inch  swing  lathe  of  this  construction 
is  shown  in  Fig.  280,  which  gives  an  excellent  idea  of  this  machine. 

It  is  impossible  in  a  lathe  of  this  character  to  so  design  it 
that  it  shall  present  a  symmetrical  contour,  however  we  may  view 
the  matter,  yet  it  seems  as  if  the  tail-stock  of  this  lathe  might  be 
somewhat  improved  in  its  outlines  without  detracting  from  its 
strength  or  usefulness. 


FIG.  280.  —  26-48  inch  Swing  Double  Spindle  Lathe,  built  by  J.  J.  McCabe. 

The  lathe  has  a  deep  and  strong  bed  and  is  well  supported  by 
cabinet  legs,  the  one  under  the  tail-stock  being  arranged  to  swivel 
to  fit  an  uneven  floor.  The  head-stock  might  be  somewhat  stronger 
to  advantage,  particularly  for  the  48-inch  swing  spindle,  but  it  is 
probably  a  fact  that  the  large  swing  feature  is  more  in  use  for  boring 
and  similar  work  than  for  heavy  work  requiring  the  full  swing. 
Still  we  know  personally  that  much  large  and  heavy  work  is  done 
on  these  lathes,  and  that  in  shops  where  such  work  is  an  exception 
rather  than  the  general  rule  the  lathe  proves  a  valuable  addition 
to  the  equipment,  saving  the  expense  of  a  large  lathe  which,  under 
ordinary  circumstances,  would  be  engaged  on  useful  work  only  a 
fraction  of  the  time. 

While  the  head-stock  and  tail-stock  are  ready  at  all  times  for 


SPECIAL   LATHES  359 

either  the  small  or  large  swing,  requiring  only  the  necessary  chang- 
ing of  face-plates  to  suit  the  work,  the  compound  rest  and  the 
center  rest  require  the  use  of  a  building-up  or  blocking  piece  when 
the  change  from  small  to  large  swing  is  made,  and  vice  versa. 
Naturally  the  compound  rest  will  not  be  as  stiff  and  rigid  as  that 
of  a  regular  48-inch  swing  lathe,  as  the  compound  rest  proper  is 
designed  upon  lines  and  with  dimensions  that  appear  to  be  a  com- 
promise between  those  of  a  26-inch  and  a  48-inch  swing  lathe. 

The  carriage  has  long  bearings  upon  the  bed  and  is  of  ample 
strength,  as  is  also  the  apron  and  its  operative  parts.  The  feed  is 
geared  and  consequently  positive  and  capable  of  the  necessary 
changes  expected  in  a  lathe  of  this  character. 

The  head-stock  cone  is  of  five  steps  and  takes  a  3J-inch  belt. 
The  head-stock  is  arranged  with  four  adjusting  screws,  by  means  of 
which  it  may  be  at  any  time  lined  up  parallel  with  the  ways  of  the 
lathe.  The  head-stock 'and  the  tail-stock  fit  on  flat  surfaces  instead 
of  V's,  thus  increasing  the  normal  swing  of  the  lathe  without  rais- 
ing the  head  spindle,  as  the  inside  V's  are  omitted.  The  tail-stock 
is  fitted  with  a  gib  on  the  front  side  for  the  purpose  of  taking  up 
any  wear  that  will  in  time  take  place,  and  is  provided  with  the 
usual  set-over  screw  for  turning  taper  work. 

The  upper  spindle  is  triple  geared  and  has  double  the  ratio  of 
back  gearing  of  the  lower  spindle,  while  the  internal  geared  face- 
plate shown  in  the  engraving  is  furnished  as  an  extra  and  gives  a 
ratio  of  72  to  1,  giving  ample  power  for  large  work. 

This  lathe  is  also  made  24-40  inch,  and  26-44  inch  swing,  while 
the  one  here  illustrated  and  described  is  also  furnished  with  per- 
manent raising  blocks  or  built  up  solid  to  swing  32-54  inches.  It 
is  also  arranged  to  run  with  an  electric  motor  when  this  method 
of  driving  is  preferred. 

A  pulley  turning  and  boring  lathe  is  shown  in  Fig.  281,  and  is 
built  by  the  New  Haven  Manufacturing  Company.  There  are 
several  features  in  this  lathe  which  make  it  of  unusual  value,  not 
only  for  turning  and  boring  pulleys,  but  for  a  variety  of  very  useful 
work. 

Among  these  are  the  following:  The  compound  rest  has  an 
unusually  long  lateral  feed.  It  may  be  set  at  any  desired  angle 
and  has  a  power  feed,  and  also  a  hand  feed  from  either  end.  The 


360 


MODERN  LATHE  PRACTICE 


compound  rest  screw  may  be  disengaged  by  lifting  a  latch  lever 
and  the  crowning  attachment  brought  into  operation. 

Ordinarily  the  crowning  of  a  pulley  is  effected  by  making  its 
two  parts  with  straight  lines,  leaving  the  angle  of  intersection  of 
these  lines  in  the  middle  of  the  face  of  the  pulley.  While  this  answers 
the  purpose  on  ordinary  pulleys,  or  pulleys  with  comparatively 
narrow  faces,  it  is  manifestly  incorrect. 

In  this  lathe  the  movement  of  the  tool  is  controlled  by  a  "  former  " 
A,  attached  to  the  fixed  part  of  the  compound  rest  and  having 
a  curved  slot  of  proper  radius  in  which  the  friction  roll  of  a  lever 
B  travels.  This  lever  is  pivoted  to  the  compound  rest  slide  and 


FIG.  281.  —  60-inch  Swing  Pulley  Lathe,  built  by  the  New  Haven 
Manufacturing  Company. 

its  upper  end  connected  to  the  compound  rest  tool  block  by  a  con- 
necting bar  which  thus  controls  the  movement  of  the  cutting- tool. 
Several  of  these  grooved  formers,  of  different  radii,  are  furnished 
with  the  lathe  for  use  with  pulleys  of  different  widths  of  face. 

Another  feature  of  this  lathe  is  the  automatic  feed  to  the  tail- 
stock  spindle  for  boring  purposes.  This  feed  is  of  13  inches  travel, 
and  readily  thrown  in  and  out  by  turning  the  knob  C.  In  boring 
pulleys  the  proper  boring  bar  is  selected,  one  end  placed  in  the  taper 
hole  in  the  tail  spindle  and  secured  by  the  clamp  dog  shown  on  the 
end  of  the  spindle.  The  opposite  end  of  this  boring  bar  fits  in  a 
bushing  in  the  head  spindle,  thus  assuring  a  correct  and  properly 


SPECIAL  LATHES  361 

aligned  hole.  While  this  work  is  being  done  the  pulley  may  be 
held  in  a  chuck,  or  chuck  jaws  attached  to  the  face-plate,  by  the  hub 
or  by  the  rim.  The  pulley  having  been  bored  is  pressed  on  an 
arbor  and  supported  on  centers.  It  is  driven  by  two  arms  secured 
by  bolts  to  the  face-plate  in  the  usual  manner. 

The  tail-stock  is  provided  with  the  usual  set-over,  the  same  as  in 
an  ordinary  engine  lathe,  for  the  purpose  of  turning  tapers.  It  is 
provided  with  two  sets  of  holding-down  bolts  so  that  the  top  casting 
with  the  spindle  may  be  set  over  without  detaching  the  tail-stock 
from  the  bed.  By  this  means  there  is  no  necessity  for  removing 
the  work  from  the  lathe  or  blocking  it  up. 

The  head  spindle  is  driven  entirely  by  means  of  the  internal 
gear  bolted  to  the  back  of  the  face-plate  through  a  pinion  on  the 
cone  shaft.  Back  gearing  is  provided  by  which,  with  the  five-step 
driving  cone,  ten  speeds  may  be  produced.  A  defect  in  the  design 
of  this  back  gearing  is  that  the  gears  are  journaled  upon  a  stud 
supported  at  only  one  end,  thus  permitting  considerable  vibration, 
which  is  liable  to  show  by  producing  chattering  of  the  tool  upon  the 
work. 

While  the  feed  is  entirely  gear  driven,  provision  is  made  for 
accidents  to  the  tool  by  making  the  gear  upon  the  end  of  the  cone 
shaft  with  a  friction  device,  by  which  it  will  be  allowed  to  slip  if 
heavy  and  unusual  strain  is  brought  upon  it,  rather  than  that  the 
gear  teeth  be  endangered. 

This  lathe  is  not  of  new  design,  but  has  been  built  in  substan- 
tially its  present  form  for  many  years;  it  is  a  deservedly  popular 
machine. 

The  ordinary  length  of  the  bed  of  this  lathe  is  about  11  feet.  It 
swings  60  inches  over  the  bed  and  50  inches  over  the  carriage  and 
will  take  in  50  inches  between  centers.  Its  weight  is  about  10,000 
pounds. 

The  head  spindle  is  bored  out  so  that  boring  bars  of  any  length 
may  be  used.  It  will  bore  and  turn  pulleys  up  to  60  inches  in 
diameter  and  19  inches  face,  and  a  pulley  up  to  50  inches  in  diameter 
and  32  inches  face. 

By  throwing  out  the  back  gears  a  fast  boring  speed  is  produced, 
or  the  boring  and  turning  may  proceed  simultanously,  if  the  pulley 
is  held  by  the  arms  on  a  proper  face-plate  fixture. 


362 


MODERN   LATHE  PRACTICE 


There  is  no  arrangement  for  the  employment  of  a  back  tool 
which  might  do  the  roughing  work.  This  fact  necessarily  limits 
needlessly  the  output  of  the  lathe,  as  a  proper  rest  for  one  or  more 
back  tools  could  be  readily  and  economically  provided. 

A  pulley-turning  lathe  may  be  so  designed  as  to  become  rather 
a  pulley-turning  machine  than  a  lathe  proper,  and  when  thus 
specialized  will  usually  be  a  more  efficient  machine  than  if  designed 
strictly  on  the  lines  of  a  lathe.  Such  a  machine  is  shown  in  Fig. 
282,  which  is  built  by  the  Niles  Tool  Works,  who  build  these  ma- 
chines for  turning  pulleys  of  30,  50,  and  60  inches  diameter. 


FIG.  282.  —  40-inch  Swing  Pulley  Turning  Lathe,  built  by  the 
Niles-Bement-Pond  Company. 

The  bed,  head-stock  and  tail-stock  are  all  cast  in  one  piece,  and 
this  casting  extends  to  the  floor  or  foundation  and  provides  a  very 
rigid  support  for  the  operative  mechanism  of  the  machine. 

The  head  spindle  is  driven  by  spiral  or  tangent  gearing,  giving 
a  very  steady  movement  entirely  devoid  of  the  tendency  to  chatter 
as  when  turning  a  pulley  or  other  light-rimmed  wheel,  when  the 
power  is  by  the  usual  spur  gearing.  By  this  device  a  much  heavier 
cut,  or  a  cut  at  a  much  coarser  feed,  may  be  successfully  carried 
and  consequently  the  time  of  performing  the  operation  much  re- 
duced. 

The  pulley  to  be  turned  is  forced  on  a  mandrel  or  arbor  and  held 
between  centers  in  the  usual  way  for  obtaining  good  concentric 
work.  As  to  the  method  of  driving  the  pulley,  there  is  an  equaliz- 


SPECIAL   LATHES  363 

ing  face-plate  which  has  arms  projecting  between  the  spokes  or 
arms  of  the  pulley  near  the  rim,  and  which  press  equally  upon  oppo- 
site sides  of  the  work  so  that  there  is  no  tendency  to  spring  the  pul- 
ley out  of  its  proper  shape,  as  is  the  case  when  it  is  held  in  a  chuck. 

There  are  two  tool-rests  which  operate  at  the  same  time,  one 
being  in  front  and  provided  with  an  angular  feed  for  crowning  the 
face  of  the  pulley,  and  one  in  the  rear  carrying  an  inverted  tool  and 
provided  with  a  hand  cross  feed.  This  lathe  tool  takes  the  rough- 
ing cut  while  the  front  tool  carries  the  finishing  cut  and  crowns  the 
pulley.  The  angular  feed  with  which  the  front  tool  is  provided 
adapts  it  for  turning  bevel  gears  as  well  as  pulleys.  When  set  to 
make  a  straight  cut  parallel  to  the  axis  of  the  work  it  is  well  adapted 
to  turning  the  outside  of  large  gear  blanks,  balance-wheels,  and  simi- 
lar work. 

While  the  tool  at  the  rear  of  the  machine  is  often  set  for  a  straight 
cut,  parallel  to  the  axis  of  the  work,  it  is  also  provided  with  an 
adjustable  slide  by  which  it  may  be  set  at  an  angle  for  crowning 
the  face  of  a  pulley  or  for  turning  bevel  gears  and  similar  work. 
This  feature  is  necesary  in  heavy  work  particularly,  in  order  to 
leave  an  equal  amount  of  metal  to  be  cut  away  by  the  front  tool 
during  its  entire  cut. 

The  driving  cone  is  of  ample  diameter;  it  is  arranged  in  six  steps 
and  carries  a  very  wide  belt.  It  runs  at  a  proper  speed  for  polish- 
ing pulleys,  as  well  as  for  driving  the  machine  for  turning  purposes, 
and  its  shaft  extends  to  the  front  as  an  arbor  or  mandrel  upon 
wiiich  the  pulley  to  be  polished  may  be  mounted  as  shown  at  A, 
Fig.  282.  A  convenient  polishing  rest  is  shown  at  B,  which  is 
used  for  this  purpose. 

This  machine  is  not  intended  for  boring  the  pulleys,  this  part 
of  the  work  being  much  more  expeditiously  performed  on  a  chuck- 
ing lathe  or  similar  machine,  which  may  be  run  at  a  much  higher 
speed  for  this  purpose. 

It  frequently  happens  that  small  work  and  that  which  must  be 
very  true  and  correct,  particularly  in  tool,  model,  and  experimental 
work,  a  comparatively  light  bench  lathe  is  much  more  convenient, 
useful  and  efficient  than  a  floor  machine  of  similar  capacity.  One 
or  more  of  these  lathes,  of  good  design  and  construction,  should 
form  a  part  of  the  equipment  of  every  tool  room,  and  of  any  room 


364 


MODERN  LATHE  PRACTICE 


in  a  general  machine  shop  or  manufacturing  plant  where  small 
work  is  done. 

Such  a  bench  lathe,  built  by  the  Waltham  Machine  Works,  is 
shown  in  Fig.  283,  and  which  is  a  good  example  of  the  best  grade 
of  American  made  bench  lathe. 

The  bed  of  the  lathe  is  32  inches  long  and  has  a  T-groove  planed 
the  entire  length  of  the  back  side.  A  bed  without  this  groove  will 
be  furnished,  if  desired,  at  a  lower  price,  but  such  a  bed  will  not 
take  all  the  attachments  that  have  been  designed  for  it.  The 
amount  of  metal  in  the  bed  is  distributed  so  as  to  give  great  stability 
and  rigidity  while  at  the  same  time  pleasing  outlines  are  presented. 
These  qualities  apply  equally  to  other  parts  of  the  lathe,  beauty 
of  design  being  one  of  its  features. 


FIG.  283.  —  8-inch  Swing  Bench  Lathe  built  by  the 
Waltham  Watch  Tool  Company. 

The  head-stock  will  swing  8  inches.  It  has  a  hardened  steel 
spindle  and  bearings,  carefully  ground  and  run  together.  It  is  very 
smooth  running  and  the  finest  work  can  be  done  with  it.  The 
pulley  has  three  steps  of  3,  4,  and  5  inches  in  diameter  and  will  take 
a  belt  1J  inches  wide.  The  larger  flange  has  three  circles  of  index 
holes,  the  numbers  being  48,  60  and  100.  The  spindle  is  adapted 
to  take  split  chucks  of  the  most  approved  pattern,  which  will 
take  wire  up  to  f  inch  in  diameter  through  its  entire  length. 

The  spindle  of  the  tail-stock  passes  entirely  through  the 
casting,  so  that  whatever  its  position  it  always  has  its  full  bearing 
(6f  inches).  It  is  graduated  to  tenths  of  an  inch,  while  the  grada- 
tions on  the  hand  wheel  read  to  1-200  inch.  The  front  side  of  the 
casting  is  cut  away  to  give  more  room  for  the  slide-rest.  By  this 
means  the  lathe  can  be  used  closer  to  the  center  than  would  other- 


SPECIAL  LATHES  365 

wise  be  the  case.  The  back  side  of  the  casting  is  reinforced  to  give 
the  necessary  stiffness. 

The  base  of  the  slide-rest  rests  directly  upon  the  bed  of  the 
lathe,  and  its  squaring  device  has  a  bearing  on  the  front  of  the  bed, 
below  the  lowest  part  of  the  head-stock  and  tail-stock.  This  gives 
the  opportunity  to  make  a  long  squaring  device,  thus  insuring 
greater  accuracy,  and  also  to  have  the  bearing  where  there  is  less  lia- 
bility of  trouble  from  chips,  dirt,  etc.  The  builders  also  make  a 
swivel  squaring  device  by  means  of  which  angles  can  be  turned  or 
ground  with  the  cross  slide,  thus  enabling  one  to  make  two  angles 
with  one  setting  of  the  slide-rest.  This  is  a  valuable  feature  in 
making  special  cutters  or  mills,  or  in  grinding  spindles  and  bearings 
having  two  angles. 

The  feed  screws  have  hardened  bearings,  and  are  provided  with 
indices  that  are  graduated  to  read  to  1-1000  inch  on  the  swivel 
screw,  and  to  1-2000  inch  on  the  cross-slide  screw,  the  latter  division 
being  adapted  so  that  the  movement  of  one  graduation  on  the 
index  will  make  a  difference  of  1-1000  inch  in  the  diameter  of  cylin- 
drical work  which  is  being  turned  or  ground. 

The  tool-slide  is  made  flat  on  top  to  take  various  attachments, 
and  has  two  T-grooves  for  the  tool-post.  Ordinary  lathe  tools  are 
used.  The  slides  are  carefully  scraped  together  and  the  whole  slide- 
rest  is  neatly  ornamented. 

For  holes  and  for  light  outside  grinding  there  is  an  inside 
grinder  that  is  arranged  so  that  the  lap  can  be  swung  away  from 
the  hole,  for  testing  the  size,  and  then  returned  instantly  to  its 
original  position. 

The  outside  grinder  for  general  work  is  clamped  directly  upon 
the  tool-slide  and  has  a  vertical  screw  adjustment.  It  is  arranged 
so  that  an  emery  wheel  can  be  used  on  either  end,  and  there  is  a 
taper  hole  in  the  front  of  the  spindle  to  take  arbors  for  small  laps. 

Two  methods  of  thread  cutting  are  provided  for.  The  first  is  on 
the  Fox  lathe  principle  and  is  attached  to  the  T-groove  on  the 
back  of  the  bed.  Any  even  multiple  of  the  lead  screw  thread  up 
to  ten  times  can  be  cut,  and  with  a  few  extra  lead  screws  all  ordi- 
nary threads  can  be  cut.  This  method  of  thread  cutting  is  the 
most  rapid,  but  under  conditions  in  which  a  great  variety  of  threads 
must  be  cut  some  machinists  will  prefer  to  use  the  slide-rest.  By 


366  MODERN  LATHE   PRACTICE 

this  style  of  thread-cutting  attachments  this  lathe  will  cut  all 
threads  from  5  to  100  per  inch,  and  all  between  5  and  50  to  the 
centimeter  can  be  cut. 

There  is  also  a  special  milling  attachment,  which  is  a  stand 
consisting  of  a  base  made  to  take  the  regular  head-stock,  and  is 
provided  with  a  slide  which  takes  the  regular  slide-rest.  The  verti- 
cal slide  has  both  a  screw  and  lever  feed,  so  arranged  that  the  change 
from  one  to  the  other  can  be  made  instantly.  A  vise  for  plain 
milling,  or  an  indexing  head  for  gear  cutting  and  cutter  making, 
can  be  attached  to  the  tool-slide  of  the  slide-rest.  This  combination 
makes  a  practical  bench  milling  machine  upon  which  a  great  variety 
of  work  can  be  done. 

While  the  descriptions  of  engine  lathes  are  confined  to  the  lathe 
proper,  leaving  the  subject  of  their  attachments  and  accessories  to 
be  treated  in  another  chapter,  it  seems  advisable  to  include  in  the 
above  description  the  various  attachments  of  this  bench  lathe,  as 
they  are  essentially  different  from  those  used  upon  or  in  connection 
with  an  engine  lathe,  and  for  different  purposes. 

In  addition  to  the  attachments  above  described  it  is  frequently 
the  case  that  others  for  special  work  are  frequently  devised  and 
added  to  the  bench  lathe  equipment,  making  it  a  very  useful  ma- 
chine and  capable  of  performing  a  great  many  different  operations, 
among  them  many  which  cannot  be  performed  on  the  regular 
engine  lathe  without  the  aid  of  expensive  attachments  and  fixtures. 
These  qualities  make  it  one  of  the  most  useful  machines  in  the  shop, 
especially  where  small  experimental  work  and  fine  tool  making,  jigs, 
and  fixtures  are  to  be  produced. 

A  plain  10-inch  swing  wood-turning  lathe  for  light  manufacturing 
work  or  for  pattern  work  is  shown  in  Fig.  284,  which  possesses  some 
peculiar  features  worthy  of  attention.  The  lathe  is  built  by  the 
F.  E.  Reed  Company. 

One  of  the  special  features  of  this  lathe  is  the  manner  of  con- 
structing the  head-stock,  a  vertical  section  of  which  is  given  in 
Fig.  285.  The  spindle  has  a  single  bearing  in  the  head-stock,  which 
extends  over  a  large  proportion  of  its  length,  the  face-plate  being 
attached  to  the  front  end  as  usual,  and  the  three-step  cone  pulley 
attached  at  the  opposite  end,  fitting  upon  the  spindle  for  a  distance 
about  equal  to  one  of  its  steps  and  carried  by  a  flanged  collar  which 


SPECIAL   LATHES 


367 


is  fastened  to  it  by  screws  and  resting  against  a  fiber  washer  with 
the  wear  or  end  thrust  taken  up  by  a  suitable  adjustable  collar  at 
the  end  of  the  spindle. 

There  is  a  ^g-inch  hole  through  the  spindle,  whose  bearing  in 
the  head  is  lysg  inches  diameter  and  7J  inches  long,  while  there  is 
also  an  outer  bearing,  formed  by  the  small  end  of  the  cone  running 
on  the  outside  of  the  head-stock,  2116-  inches  diameter  and  3f  inches 
long,  giving  50  square  inches  of  wearing  surface  in  the  head-stock, 
which  is  at  least  three  times  more  than  is  obtained  in  the  head- 
stock  of  an  ordinary  wood-turning  lathe  of  this  swing. 


FIG.  284.  —  10-inch  Swing  Wood  Turning  Lathe,  built  by  the 
F.  E.  Reed  Company. 

The  head  spindle  is  a  crucible  steel  forging,  and  runs  in  com- 
pressed genuine  babbitt  metal  bearings,  special  care  being  used  to 
make  the  inner  and  the  outer  bearings  truly  cylindrical  and  con- 
centric with  each  other. 

As  to  the  wearing  qualities  of  these  head-stocks  the  manu- 
facturers say: 

"We  have  made  and  sold  over  six  hundred  of  these  lathes 
during  the  last  eight  years.  For  over  six  years  we  have  had  one 
of  them  in  constant  use  in  our  works  as  a  polishing  lathe.  This 


368 


MODERN  LATHE   PRACTICE 


is  very  severe  usage  for  a  lathe,  but  during  all  this  time  it  has 
required  absolutely  no  repairs,  and  no  special  attention  beyond 
seeing  that  it  was  kept  properly  oiled  with  a  good  quality  of  lubri- 
cating oil.  We  have  a  large  number  of  most  excellent  testimonials 
from  schools  that  have  used  these  wood  lathes  for  a  number  of 
years." 

The  countershaft  is  of  very  simple  construction  and  of  similar 
design  to  the  head-stock.  In  place  of  the  usual  tight  and  loose 
pulley  with  the  belt  operated  by  a  shipper  rod  and  lever,  the  belt 


FIG.  285.  —  Head-Stock  of  Reed  Wood  Turning  Lathe. 

fork  is  handled  by  a  vertical  rod,  the  lower  end  of  which  hangs  in  a 
position  convenient  to  the  operator,  who  has  only  to  give  it  a  turn 
to  the  right  or  left  by  means  of  a  short  handle  to  start  and  stop  the 
lathe. 

The  V's  in  the  bed  are  inverted,  or  planed  out,  and  the  head 
and  tail  stocks  are  fitted  into  them,  instead  of  upon  them,  which 
is  the  usual  way.  This  allows  a  perfectly  free  and  level  surface 
across  the  top  of  bed  and  shelf  on  back  side,  without  any  obstruc- 
tion, besides  protecting  the  V's  from  being  jammed.  The  upper 
angle  of  V  is  rounded  where  it  meets  the  surface  of  the  bed,  which 
also  prevents  jamming  or  injury  of  the  bed  or  V  at  this  place. 

The  T-rests,  instead  of  being  the  usual  form,  are  concaved,  with 
a  projecting  lip  on  the  bottom  which  serves  as  a  finger  gage  for 
the  operator  while  using  the  turning  tool.  The  T-rest  holder  is 


SPECIAL  LATHES  369 

secured  to  the  bed  by  a  clamping  device  that  is  neat,  strong,  and 
quickly  operated.  There  is  a  shelf  on  the  back  side  of  the  lathe, 
parallel  with  the  top  of  the  bed,  and  of  the  same  height;  another 
shelf  is  also  furnished  underneath  the  bed,  as  shown  in  the  engrav- 
ing. A  hook  or  holder,  with  proper  support  for  the  same  is  shown. 
This  is  for  holding  a  blue  print,  or  sample  of  the  work,  before  the 
operator,  and  can  be  raised  or  lowered.  The  form  of  the  lathe  bed 
in  connection  with  the  extra  speed  of  the  legs,  and  the  manner  of 
attaching  the  lower  shelf,  all  combine  to  insure  steadiness  of  the 
lathe  when  run  at  the  high  speed  for  which  it  is  designed;  and  each 
lathe  is  run  five  hours  at  2,600  revolutions  per  minute  before  leaving 
the  works,  to  see  that  it  is  in  every  respect  right. 

The  workmanship  on  this  lathe  is  fully  up  to  the  standard  of  the 
work  usually  done  by  this  company,  which  is  sufficient  guarrantee 
of  its  quality. 


CHAPTER  XX 

REGULAR   TURRET   LATHES 

Importance  of  the  turret  lathe.  Its  sphere  of  usefulness.  Classification  of 
turret  lathes.  Special  turret  lathes.  The  monitor  lathes.  The  Jones  & 
Lamson  flat  turret  lathe.  Its  general  design  and  construction.  Its 
special  features.  Its  tools.  The  Warner  &  Swasey  24-inch  swing  uni- 
versal turret  lathe.  Ganeral  description.  Its  capacity.  Taper  turning 
attachment.  Its  speeds.  The  Bullard  Machine  Tool  Company's  26- 
inch  swing  complete  turret  lathe.  Its  massive  form  and  its  general  design 
and  construction.  Lubrication  of  tools.  The  countershaft.  The  Pratt  & 
Whitney  3  by  36  turret  lathe.  Its  special  features.  Its  general  desing. 
Its  capacity.  Special  chuck  construction  and  operation.  The  Gisholt 
turret  lathe.  Its  massive  design  and  construction.  Its  large  capacity. 
Its  general  and  special  features.  The  Pond  rigid  turret  lathe.  Its  heavy 
and  symmetrical  design.  Detailed  description.  Its  operation.  Gen- 
eral dimensions. 

WHILE  the  regular  engine  lathe  is  in  almost  universal  use  wher- 
ever machine  work  is  done,  and  while  it  is  the  one  indispensable 
tool  in  every  machine  shop,  the  modifications  of  it  in  the  various 
forms  of  a  turret  lathe  are  becoming  second  only  in  the  importance 
and  the  range  of  its  work.  So  great  has  been  the  advance  in  this 
respect  during  recent  years  that  nearly  all  machine  shops,  even 
small  jobbing  shops,  are  not  considered  as  possessing  a  passably 
modern  equipment  without  one  or  more  turret  lathes. 

Formerly  it  was  not  thought  worth  while  to  " set  up"  a  job  on 
a  turret  lathe  unless  there  were  fifty  or  more  pieces  of  the  same  kind 
to  be  machined.  It  is  now  a  common  occurrence  to  use  the  turret 
lathe  when  only  half  a  dozen  pieces  of  a  kind  are  to  be  made.  The 
reasons  for  this  are  that  formerly  special  tools  had  to  be  made  for 
many  of  the  jobs  attempted,  whereas  now  we  have  a  great  many 
regular  tools  furnished  with  the  turret  lathe  that  are  of  such  form 
and  construction  as  to  be  available  for  nearly  all  the  ordinary  turret 

370 


REGULAR  TURRET  LATHES  371 

lathe  jobs,  while  the  addition  of  an  extra  tool  now  and  then  for 
special  work,  or  a  special  form,  will  adopt  the  turret  lathe  for  a  very 
large  variety  of  work,  which  may  thus  be  performed  with  a  great 
degree  of  accuracy,  with  a  very  good  finish  and  in  a  very  economical 
manner. 

Where  large  numbers  of  pieces  of  the  same  kind  are  to  be  made, 
it  is  usually  the  practice  to  make  special  tools  whenever  better 
work  or  a  larger  output  can  be  thereby  secured.  This  will  be 
largely  a  matter  of  practical  judgment  of  the  man  in  charge  of  the 
work. 

We  may  divide  the  turret  lathe  proper,  and  the  engine  lathes 
when  used  as  turret  lathes  by  the  addition  of  a  turret,  into  five 
classes,  according  to  their  design  and  methods  of  operation,  namely : 

First,  the  engine  lathe  serving  as  a  turret  lathe  by  mounting  a 
hand-revolved  turret  upon  its  carriage,  in  place  of  the  usual  com- 
pound rest. 

Second,  the  engine  lathe  serving  as  a  turret  lathe  by  mounting 
a  hand-revolved  turret  upon  the  bed  by  means  of  a  shoe  or  saddle 
which  supports  the  turret  slide. 

Third,  a  turret  lathe  proper,  built  as  such,  with  a  turret  pivoted 
to  a  slide  supported  by  a  shoe  or  saddle;  the  turret  being  revolved 
and  fed  by  hand. 

Fourth,  a  turret  lathe  similar  to  the  last  and  sometimes  called 
a  " semi-automatic  turret  lathe,"  in  which  there  is  a  power  feed  on 
the  cut  and  the  turret  is  revolved  automatically  at  the  end  of  the 
stroke. 

Fifth,  a  complete  automatic  turret  lathe  with  power  feed  on  the 
cut,  a  quick  power  return,  and  the  turret  automatically  revolved 
at  the  end  of  the  stroke. 

Those  in  the  third,  fourth,  and  fifth  classes  are  usually  provided 
with  a  cut-off  slide  carrying  one  tool  in  front  and  frequently  an 
inverted  tool  at  the  back. 

Various  examples  of  these  different  classes  will  be  illustrated 
and  described  in  the  following  pages,  giving  the  designs  built  by 
several  of  the  prominent  manufacturers  of  this  type  of  machines. 

There  are,  of  course,  special  machines  of  this  general  type  of 
lathes  built  for  special  purposes.  There  are  modifications  of  the 
general  class,  into  the  details  of  which  it  is  impossible  to  go  in  these 


372  MODERN   LATHE  PRACTICE 

pages,  since  it  is  the  object  to  present  distinct  types  or  classes,  rather 
than  to  expand  this  work  to  the  dimensions  of  a  cyclopedia  on  the 
subject  of  lathes. 

There  is  one  type  that  deserves  special  attention  on  account  of 
its  valuable  service  on  small  work,  and  that  has  been  known  in  the 
shop  for  many  years  as  a  "monitor"  lathe, from  the  fact,  no  doubt, 
of  its  resemblance  to  the  turret  of  a  monitor.  The  slide  upon  which 
the  turret  is  pivoted  is  run  forward  and  back  by  a  lever  which  makes 
it  very  rapid  in  operation.  It  is  usually  built  for  small  work  only. 

The  Jones  &  Lamson  flat  turret  lathe  is  now  so  well  known  that 
an  extended  description  of  it  seems  hardly  necessary,  and  yet  its 
importance  in  the  manufacturing  world  of  to-day,  and  its  many 
points  of  real  mechanical  interest  and  importance,  demand  more 
than  a  passing  notice. 

A  front  view  of  one  of  these  machines  is  given  in  Fig.  286,  this 
particular  machine  being  3  x  36-inch  size,  that  is,  it  will  work  up  a 
3-inch  bar  and  the  turret  has  a  run  of  36  inches  on  the  bed. 

As  will  be  seen  the  bed  is  supported  by  strong  and  well  designed 
legs  in  a  pan  nearly  the  full  size  of  the  machine.  The  head-stock 
and  its  gearing  is  covered  by  a  protecting  case  which  moves  with 
it.  One  of  the  peculiar  features  of  the  machine  being  the  sliding 
head  which  has  a  transverse  movement  for  the  purpose  of  increasing- 
its  effective  working  capacity.  The  turret  is  mounted  upon  a 
saddle  fitted  to  broad  V's  upon  which  it  has  a  long  bearing,  insuring 
accurate  results. 

The  turret  is  a  flat  circular  plate  and  is  mounted  on  a  low  car- 
riage containing  controlling  mechanism.  The  connections  of  the 
turret  to  the  carriage,  and  the  carriage  to  the  lathe  bed,  are  the  most 
direct  and  rigid,  affording  absolute  control  of  the  cutting-tools. 
The  turret  is  accurately  surfaced  to  its  seat  on  the  carriage  by  scrap- 
ing, and  securely  held  down  on  that  seat  by  an  annular  gib.  In  the 
same  manner  the  carriage  is  fitted  to  the  V's  of  the  bed;  the  gibs 
passing  under  the  outside  edge  of  the  bed.  The  breadth  of  this 
bridge  across  from  V  to  V  makes  an  unyielding  mass  to  which  the 
tools  can  be  affixed. 

The  indexing  mechanism  of  the  turret  is  of  the  greatest  impor- 
tance, and  in  this  particular  point  the  flat  turret  lathe  seems  to 
have  an  exceptional  advantage.  Its  index  pin  is  located  directly 


REGULAR  TURRET  LATHES 


373 


under  the  working  tool,  and  so  close  to  it  that  there  can  be  no  lost 
motion  between  the  tool  and  the  locking  pin.  The  turret  is  turned 
automatically  to  each  position  the  instant  the^tool  clears  the  work 
on  its  backward  travel,  and  it  is  so  arranged  that  by  raising  and 


lowering  trip  screws  near  the  center  of  the  turret  it  may  be  turned 
to  three,  four,  or  five  of  the  six  places  without  making  any  other 
stops.  ) 

The  power  feed  for  the  carriage  is  actuated  by  a  worm-shaft. 


374  MODERN   LATHE   PRACTICE 

The  worm  is  held  into  its  wheel  by  a  latch  which  is  disengaged  by 
the  feed  stops.  There  are  six  feed  stops,  one  for  each  position  of  the 
turret,  and  they  are  independently  adjustable.  This  feature  of 
an  independent  stop  for  each  tool  will  be  appreciated  by  the  users 
of  the  other  turret  lathes,  some  of  which  have  only  one  stop  for 
all  turret  tools.  These  feed  stops  are  notched  flat  bars  placed  side 
by  side  in  the  top  of  the  bed.  They  also  serve  as  a  positive  stop. 

The  head-stock  is  of  such  great  importance  that  weakness  here 
would  mean  a  weak  link  in  the  chain.  Greatest  care  has  been 
exercised  to  make  the  head-stock  equal  in  stiffness  to  the  turret. 

The  spindle  is  ground  to  size,  and  its  phosphor-bronze  bearings 
are  scraped  to  give  a  perfect  contact.  A  2J-inch  hole  extends  from 
end  to  end,  through  which  the  bars  of  stock  pass. 

The  caps  to  the  spindle  bearings  are  fitted  over  large  hollow 
posts  which  make  the  top  half  of  the  box  practically  as  rigid  as  the 
lower  half. 

The  cone  and  large  gear  are  loose  on  the  spindle  and  connected 
at  will  by  friction  clutches.  The  large  gear  is  covered  with  a  hood 
which  protects  it  from  chips  and  dirt,  ensuring  smooth  running. 
The  back  gear  is  placed  below  the  cone  in  the  head,  and  a  triple 
back  gear,  when  required,  is  placed  beneath  the  regular  back  gear. 
The  regular  back  gear  gives  a  4  to  1  proportion,  and  the  triple  gear 
makes  a  16  to  1  speed.  The  triple  gear  is  required  for  all  standard 
screw  threads  above  If  inches  in  diameter,  and  in  chucking  work  of 
large  diameter. 

The  die  carriage  carries  a  die  of  any  kind,  and  a  pointer  for  sha- 
ping the  end  of  a  shaft  or  bolt.  This  carriage  is  mounted  on  a 
sliding  bar  and  arranged  to  swing  into  wrorking  position.  It  is 
provided  with  lugs  which  take  bearing  on  the  top  of  the  cross- 
slide,  which  tool  must  be  in  operative  position  when  the  die 
carriage  is  used.  The  pointing  tool  may  be  used  as  a  turner  for 
reducing  the  stock. 

The  bed  rests  on  a  "  three-point "  bearing,  making  it  impossible 
to  twist  or  vary  the  deflection  of  the  bed  by  an  unsteady  or  un- 
natural foundation. 

A  drainage  bed  and  double  overflow  reservoir  with  circular 
pump  are  clearly  shown  in  the  engraving,  and  are  too  simple  to 
need  explanation. 


REGULAR  TURRET  LATHES 


375 


The  head  receives  its  power  through  a  triple  friction  counter- 
shaft of  unusual  proportions  and  running  speed.  The  three  friction 
pulleys  are  12  inches  in  diameter  by  4  inches  face;  two  run  300  revolu- 
tions per  minute,  and  the  remaining,  or  middle,  pulley  runs  150 
revolutions  per  minute. 


FIG.  287.  —  Top  View  of  Turret  Parts  of  Jones  &  Lamson  Flat  Turret  Lathe. 

These  pulleys  have  extra  long  hubs  that  extend  an  equal  distance 
each  side  of  the  "pull  of  the  belt"  (each  side  of  the  rim),  and  per- 
fectly distribute  that  strain  over  its  entire  bearing  on  the  shaft. 
The  shipper  rod  is  so  connected  that  it  will  act  on  any  one  of  the 
three  clutches  at  the  will  of  the  operator. 

The  tools  used  in  this  machine  are  of  the  usual  nature  but  of 
improved  design  in  many  cases,  and  are  well  shown  in  Fig.  287,  as 


376 


MODERN  LATHE  PRACTICE 


they  appear  on  the  machine,  in  the  top  view  taken  from  the  rear 
end,  and  at  the 'front  of  the  machine,  looking  toward  the  head-stock. 

The  machine  tools  built  by  Warner  &  Swasey  are  known  wher- 
ever American  machines  are  used  as  being  of  good  design,  good 
materials,  and  good  workmanship.  In  fact,  some  of  the  finest  ma- 
chine work  turned  out  in  this  country  comes  from  their  shop. 

Their  turret  lathes  are  no  exception  to  this  rule,  and  in  Fig.  288 
is  shown  their  24-inch  swing  universal  turret  lathe,  which  is  a  good 
example  of  a  lathe  of  this  type,  adapted  to  a  large  variety  of  work 
such  as  iron  and  brass  valves,  from  3  to  6  inches,  gears,  pulleys, 
bearings,  machine  parts  of  circular  contour,  and  general  chucking 
work  requiring  drilling,  reaming,  and  facing. 


FIG.  288.  —  24-inch  Universal  Turret  Lathe,  built  by  Warner  &  Swasey. 

The  bed  is  8  feet  7  inches  long,  and  is  deep  and  heavily  ribbed 
as  it  should  be  in  a  lathe  of  this  kind.  The  head-stock  is  cast  in 
one  piece  with  the  bed,  rendering  it  strong  and  rigid  against  the 
weight  of  the  work  and  the  torsional  strain  of  the  machining  opera- 
tions. The  spindle  cone  is  of  three  steps,  the  largest  of  which  is 
16  inches  in  diameter  and  adapted  for  a  4-inch  belt.  The  spindle 
has  a  2J-inch  hole  all  the  way  through.  From  the  end  of  the  spindle 
nose  to  the  face  of  the  turret  is  36  inches  when  at  its  extreme 
position. 

The  friction  back  gears  give  two  speeds  without  stopping  the 
machine,  the  ratio  being  8  to  1. 

The  turret  is  hexagonal  in  form  and  has  a  very  large  bearing 
upon  the  carriage.  It  is  14  inches  across  flats  and  has  six  3-inch 


REGULAR  TURRET  LATHES  377 

holes,  allowing  2J-inch  bars  to  pass  through  it.  The  carriage  has 
a  longitudinal  travel  of  32  inches  and  a  cross  travel  of  12  inches. 

Two  sets  of  independent  adjustable  stops  are  provided  for  each 
face  of  the  turret,  one  operating  with  the  longitudinal  and  the  other 
with  the  cross  travel  of  the  carriage.  When  the  general  work  which 
the  lathe  is  expected  to  do  renders  these  stops  superfluous,  they  may 
be  omitted  from  the  regular  equipment. 

The  geared  feeds,  both  for  the  longitudinal  and  the  cross  cuts, 
give  six  changes,  any  one  of  which  is  made  instantly  available  by 
moving  a  lever.  These  feeds  are  so  designed  that  they  will  give 
respectively  4,  7, 12,  16,  28,  and  48  to  the  inch  for  every  revolution 
of  the  main  spindle;  that  is,  the  spindle  will  make  these  various 
number  of  revolutions  while  the  feeds  advance  1  inch. 

The  lead  screw  is  provided  with  the  proper  gears  for  cutting  2, 
3,  4,  5,  6,  7,  8,  9, 10, 11},  12,  and  14  threads  per  inch.  Finer  threads 
than  these  are  not  likely  to  be  required  on  a  lathe  of  the  capacity 
of  this  one. 

There  is  a  taper  turning  attachment  for  turning  tapers  up  to 
3  inches  per  foot,  which  is  furnished  only  when  specially  required. 

The  machine  is  driven  from  a  triple  friction  countershaft  which 
has  16-inch  pulleys  adapted  for  a  4}-inch  belt.  One  of  these  pulleys 
runs  at  a  speed  of  100  revolutions  per  minute  and  the  other  at  140, 
which  gives  twelve  spindle  speeds  ranging  from  53  to  264  per  minute 
without  the  back  gears,  and  from  7  to  30  revolutions  per  minute 
when  the  back  gears  are  in  use.  A  third  pulley  is  designed  to 
run  the  spindle  backwards. 

The  weight  of  this  machine  is  4,500  pounds,  which  shows  its 
substantial  and  massive  character. 

This  firm  make  a  variety  of  styles  and  sizes  of  turret  lathes 
adapted  to  a  large  class  of  products. 

The  Bullard  Machine  Tool  Company  enjoy  a  reputation  for 
turning  out  first-class  machines.  This  applies  equally  to  the 
design,  the  material,  and  the  workmanship. 

In  Fig.  289  is  shown  one  of  their  26-inch  swing  complete  turret 
lathes,  or  as  might  be  more  comprehensively  termed,  turret  machines 

The  machine  is  of  massive  design,  the  bed  deep  and  strongly 
braced.  It  is  provided  with  heavy  top  members  or  tracks,  carrying 
broad  V's,  and  surrounded  by  a  proper  pan  for  catching  and  carry- 


378 


MODERN  LATHE  PRACTICE 


ing  off  whatever  lubricating  material  is  used.  The  bed  is  well 
supported  at  the  head  end  by  a  broad  cabinet,  made  long  enough 
to  furnish  a  solid  support  under  the  front  box  of  the  main  spindle. 
At  the  rear  end,  where  much  less  support  is  required,  a  leg  is  deemed 
sufficient. 


The  head-stock  is  of  ample  length  to  furnish  large  housings  for 
the  main  spindle  boxes,  as  well  as  sufficient  space  for  a  three-step 
cone  of  liberal  dimensions  and  the  necessary  back  gears,  clutches, 
etc.  The  largest  section  of  the  cone  is  16  inches  in  diameter  and 


REGULAR  TURRET   LATHES  379 

adapted  for  a  4|-mch  belt.  The  spindle  is  bored  out  to  3|  inches 
and  is  fitted  with  a  chuck  of  suitable  design  for  taking  hexagonal, 
square,  or  round  bars.  The  spindle  is  driven  by  triple  gearing  and 
is  fitted  with  a  patented  friction  clutch  for  instantly  changing  from 
belt  speeds  to  either  set  of  gears  without  stopping.  The  change  to 
back  gears  is  made  by  moving  the  clutch  lever,  and  to  the  triple 
gears  by  means  of  the  lever  shown  on  the  back  of  the  front  spindle 
bearing,  thus  obtaining  three  speeds  from  the  cone,  three  through 
the  double  train  of  gears,  and  three  through  the  triple  train  of  gears, 
making  nine  spindle  speeds  in  all.  , 

The  carriage  is  designed  to  be  heavy  and  strong  and  has  a  long 
bearing  upon  the  bed,  to  which  it  is  securely  gibbed.  It  is  provided 
with  a  taper  attachment,  reversible  cross  and  lateral  feeds,  which 
are  driven  by  gearing  from  a  splined  lead  screw,  the  thread  of 
which  is  used  only  for  thread  cutting,  thus  insuring  accurate  work 
of  this  kind.  At  the  front  of  the  bed  and  directly  below  the  large 
step  of  the  spindle  cone  are  seen  the  carriage  stops,  which  are  ad- 
justable in  a  group  upon  the  bed,  and  independently  as  the  work 
may  require. 

The  cross-slide  is  unusually  wide  and  is  operated  by  a  screw  and 
a  three-ball  crank.  There  are  three  tool-posts  so  that  forming  cuts 
may  be  made  as  well  as  the  usual  cutting-off  operation  performed. 

The  turret  is  hexagonal  in  form  and  14  inches  across  the  flat 
surfaces.  The  tool  holes  are  3J  inches  diameter  and  the  center 
stud  is  drilled  with  a  hole  of  the  same  diameter  so  as  to  allow  a  bar 
to  pass  entirely  through.  The  tool  faces  are  also  drilled  with  four 
holes  each  for  use  in  bolting  on  large  tool-holders.  The  turret  is 
provided  with  an  automatic  feed  and  trip,  and  with  a  patented 
device  for  unlocking  and  revolving  it  at  any  point  between  8  and 
22  inches  of  its  run.  It  is  pivoted  upon  a  long  top  slide  provided 
with  stops  at  the  rear  end  and  may  be  operated  by  the  automatic 
feed  or  by  the  capstan  levers  in  the  usual  manner.  The  top  slide 
is  well  supported  by  a  long  and  broad  bottom  slide  or  base,  firmly 
clamped  at  any  point  on  the  bed,  and  moved  along  the  bed  by  a 
rack  and  pinion  device. 

The  lubrication  of  tools  is  amply  provided  for,  the  lubricant  being 
pumped  from  a  tank  on  the  floor  and  up  through  two  pipes  properly 
jointed  so  as  to  deliver  two  streams  of  lubricating  compound  at  a 


380 


MODERN  LATHE  PRACTICE 


I 


time  at  the  points  desired.  Situated  over  this  tank  and  beneath 
the  pan  surrounding  the  bed,  is  a  secondary  pan  supported  on  wheels 
so  as  to  be  readily  removable  when  it  is  desired  to  clean  it  out.  Into 
each  end  of  this,  oil  and  chips  drip  from  the  two  lips  seen  at  the 

right  and  left.    This  feature 
"  ^^^s\        will  be  duly  appreciated  by 
I  .      the  operator,  who  has  been 
/f    §     accustomed  to  clean  out  the 
/  &     pans  of  the  older  style  ma- 

chines. 

The  countershaft  has  three 
friction  pulleys  20  inches  in 
diameter,  for  4  J-inch  belt,  and 
runs  respectively  96  and  144 
revolutions  per  minute  for- 
ward and  144  revolutions 
backward.  The  weight  of 
the  entire  machine  is  9,500 
pounds,  which  is  a  very  lib- 
eral weight  for  a  machine  of 
this  capacity,  and  insures 
great  rigidity  and  strength  of 
its  principal  parts. 

Another  notable  machine 
brought  out  by  the  Pratt  & 
Whitney  is  their  3  x  36  tur- 
ret lathe;  that  is,  a  lathe  ca- 
pable of  handling  a  3-inch 
bar  of  round  stock  and  in 
which  the  turret  has  a  run  of 
36  inches.  The  machine  is 
well  shown  in  perspective  in 
Fig.  290  and  a  plan  of  it  is  given  in  Fig.  291. 

As  may  be  assumed  from  its  capacity  it  is  a  very  rigid  machine 
in  which  the  bed,  head-stock  and  pan  are  cast  in  one  piece.  On 
account  of  the  great  quantity  of  oil  that  is  necessary  to  use  upon  it 
when  machining  bar  stock,  the  bed  is  set  in  a  pan  of  ample  propor- 
tions and  well  supported  on  heavy  legs,  those  under  the  head-stock 


JS 


H 

1 
i 

X 

CO 


REGULAR  TURRET   LATHES  381 

being  very  broad  and  furnishing  a  support  under  the  entire  length 
of  the  head-stock.  The  compound  casting  for  bed,  head-stock, 
and  pan  is  shown  in  Fig.  291. 

One  of  the  new  features  of  the  machine  is  the  chuck,  which  is 
arranged  to  handle  bar  stock  considerably  above  or  below  size  with 
the  same  gripping  force  as  if  the  bar  were  true  to  size.  This  is  a 
feature  of  much  value  in  machining  the  larger  sizes  of  rough  stock 
in  which  there  is  usually  considerable  variation  in  the  diameter  even 
at  different  points  along  the  same  bar,  as  well  as  the  frequent  occur- 
rance  of  slight  bends  in  the  bar  that  render  it  difficult  to  handle  in 
the  ordinary  turret  lathe  chuck. 


FIG.  291.  —  The  Single  Casting  Combining  the  Bed,  Head-Stock  and  Pan  of  the 

Pratt  &  Whitney  Turret  Lathe. 

This  machine  is  regularly  driven  by  a  three-step  cone  pulley 
adapted  for  broad,  double  belts.  This  cone  pulley,  in  conjunction 
with  the  double  friction  back  gears  and  a  three-speed  countershaft 
of  improved  design,  gives  to  the  main  spindle  twenty-seven  speeds, 
or  nine  for  each  step  of  the  cone.  These  nine  different  speeds  with 
an  open  belt  range  from  78  to  550  revolutions  per  minute,  and  the 
eighteen  back  gear  speeds  run  from  O^Q-  to  182  revolutions  per 
minute.  This  great  range  of  speed  adapts  the  machine  to  handling 
all  work,  not  only  from  3  inches  in  diameter  down,  but  all  classes  of 
materials  as  well,  so  that  it  does  its  work  under  a  very  large  range 
of  conditions  and  circumstances. 

The  turret  slide  has  power  feed  for  turning  lengths  up  to  36 
inches,  and  the  driving  device  for  the  feed  mechanism  for  the  turret 
and  cross-slides  is  by  means  of  a  silent  chain  which  is  driven  from 
a  sprocket  wheel  on  the  spindle,  from  whence  it  leads  down  to  a 
gear  box  containing  the  variable  speed  gears  for  giving  the  different 
rates  of  feed.  The  shaft  for  operating  the  turret  and  cross-slide 


382 


MODERN  LATHE  PRACTICE 


located  at  the  rear  of  the  bed,  and  the  gear  box  mechanism  is  oper- 
ated by  the  two  short  levers  in  front  of  the  head-stock  as  seen  in 
Fig.  290,  and  by  which  four  rates  of  feed  in  either  direction  are 
obtained  for  either  the  turret  slide  or  the  cross-slide.  The  turret 

feeds  range  from  .007  to  0.23  inches 
and  those  of  the  cross-slide  from  .0014 
to  .004  inches  per  revolution  of  the 
main  spindle. 

There  are  dovetailed  upper  and 
lower  edges  on  the  hexagonal  turret 
faces,  to  wrhich  tools  may  be  rigidly 
clamped,  and  each  tool  is  provided 
with  an  independent  stop  which  is  car- 
ried in  an  adjustable  bracket  fixed  to 
the  front  of  the  bed. 

By  referring  to  the  plan  view  of  the 
machine  in  Fig.  292,  at  X,  it  will  be 
seen  that  there  are  six  stops  placed  side 
by  side  in  the  bracket  above  referred  to. 
Each  one  of  these,  when  adjusted,  is 
held  by  an  independent  screw.  As  the 
turret  is  rotated  a  cam  at  the  bottom 
operates  an  arm  carried  on  a  rock-shaft 
at  the  side  of  the  turret  slide  and 
swings  it  into  line  with  the  proper 
stop  in  the  bracket.  This  rocker  arm, 
or  turret  stop,  is  always  rigidly  sup- 
ported, as  in  all  positions  the  rear 
face  rests  against  a  machined  surface 
on  the  slide. 

The    cross-slide    carries  two    tool- 
posts  of  good  design  for  holding  tools 
rigidly,  and  may  be  adjusted  at  any 
point  along  the  bed  that  the  work  re- 
quires by  a  hand  wheel  at  the  front  end  of  the  head-stock 

The  peculiar  construction  of  the  chuck  referred  to  above  is 
worthy  of  special  attention  and  may  be  understood  by  reference  to 
the  sectional  engravings  and  the  following  description  of  its  mechan- 


REGULAR  TURRET  LATHES 


383 


ism.  In  Fig.  293  is  shown  a  section  of  the  chuck  and  its  related 
parts,  and  in  Fig.  294  its  operative  mechanism.  In  the  former  en- 
graving D  is  a  portion  of  the 
nose  of  the  spindle,  and  E  the  cap 
screwing  on  over  it.  G  is  the 
chuck  jaws  and  H  the  closing  col- 
lar. This  collar  as  well  as  the 
jaws  of  the  chuck  and  the  wearing 
surfaces  of  the  cap  are  hardened 
and  ground,  and  the  rear  end  of 
the  latter  is  made  a  sliding  fit  in 
the  spindle  bore,  while  its  front 
end  is  ground  to  a  sliding  fit  in  FIG.  293. — Chuck  Construction  of  the 


the  ring  F,  which  is  hardened  and 


Pratt  &  Whitney  Turret  Lathe. 


forced  into  the  nose  of  the  spindle  D,  and  then  ground  while  the 
spindle  is  running  in  its  own  journal  boxes. 

The  chuck  jaws  have  square  shoulders  abutting  against  the  cap 
and  open  and  close  without  end  movement,  as  the  spring  plugs 


FIG.  294.  —Chuck  and  Rod  Feed  Mechanism  of  the  Pratt  &  Whitney 

Turret  Lathe. 

keep  them  in  contact  with  the  cap  when  released  by  the  closer. 
The  jaws  for  each  nominal  size  of  stock  are  adapted  to  hold  bars 
332  inch  over  size,  or  ^  mcn  under  size,  and  anywhere  within 
this  range  they  maintain  a  parallel  grip  on  the  bar.  This  is  due  to 


384  MODERN  LATHE  PRACTICE 

the  fact  that  the  contact  between  jaws  and  closer  is  always  a  line 
contact  along  the  middle  of  each  jaw,  the  surface  at  either  side  of 
this  line  being  relieved  so  as  always  to  clear  the  conical  seat  in  the 
closer. 

To  give  the  jaws  a  uniform  gripping  pressure  upon  the  work, 
regardless  of  the  variation  in  size  from  standard,  provision  is  made 
for  first  bringing  them  into  contact  with  the  bar  by  operating  a 
lever,  after  which  they  are  closed  tight  by  means  of  a  second  lever, 
both  levers  being  mounted  at  the  front  of  the  head  and  about  a 
common  axis,  as  shown  in  Fig.  290. 

Referring  again  to  Figs.  292  and  294  it  will  be  seen  that  the 
rear  end  of  the  spindle  carries  two  sliding  rings  actuated  by  inde- 
pendent yoked  levers;  these  latter  are  connected  by  links  with  the 
operating  levers  just  mentioned. 

The  ring  C,  Fig.  293,  is  fitted  with  a  pair  of  racks  each  of  which 
engages  with  a  -spiral  pinion  formed  at  the  center  of  a  right  and 
left-hand  screw;  the  front  ends  of  the  screws  fit  holes  tapped  in 
collar  A,  which  is  secured  to  the  spindle,  while  the  rear  ends  are 
screwed  into  the  sleeve  B  which  carries  the  chuck-closing  fingers  J, 
whose  heels  are  always  in  contact  with  the  lugs  of  the  chuck-closing 
tube  K,  the  rollers  at  the  outer  ends  resting  against  the  shoes 
carried  in  the  ring  I.  The  yoked  lever  N,  operated  through  the  link 
0  by  the  inner  of  the  two  vertical  levers  in  front  of  the  head,  is  con- 
nected also  by  the  slotted  link  L  with  the  stock-feed  mechanism  at 
the  rear. 

When  the  chuck  is  opened  and  the  stock  stop  swung  down  from 
the  head,  the  inner  lever  is  thrown  over,  forcing  the  link  L  toward  the 
rear  and  clutching  the  gear  M  to  the  feed  screw,  which  is  then  driven 
from  the  spindle  in  the  right  direction  to  draw  the  bar  forward 
against  the  stock.  When  the  bar  is  in  contact  with  the  stop  the 
clutch  throws  to  the  middle  position  as  shown,  stopping  the  screw; 
the  lever  is  then  thrown  in  the  opposite  direction,  sliding  the  ring  C 
on  its  bearing,  and  by  means  of  the  racks,  spiral  gears  and  right  and 
left-hand  screws  the  sleeve  B,  with  fingers  J  and  tube  K,  is  drawn 
forward,  forcing  the  chuck  jaws  into  contact  with  the  bar.  The 
outer  lever  is  then  operated  to  push  back  the  ring  I  and  close  the 
chuck  down  hard  upon  the  work. 

The  manipulation  of  the  levers  takes  but  an  instant,  and  it  will 


REGULAR  TURRET  LATHES  385 

be  noticed  that  no  matter  what  the  position  of  the  closing  tube  K 
may  be  when  the  jaws  are  in  contact  with  the  stock,  the  pressure 
exerted  through  the  fingers  J  and  the  sliding  ring  I  is  always  uni- 
form and  effective. 

The  upright  at  the  outer  end  of  the  stock-feeding  apparatus 
carries  an  adjustable  rotating  support  for  the  bar  stock,  and  the 
traversing  bracket  R  actuated  by  the  screw  is  adapted  to  receive 
various  sizes  of  bushings  corresponding  to  the  collars  secured  to  the 
stock. 

When  the  feed  bracket  has  reached  its  extreme  forward  position 
it  is  run  back  by  moving  to  the  left  the  short  lever  shown  in  Fig. 
290,  which  clutches  the  reversing  gear  M  to  the  screw.  The  clutch 
between  gears  M  and  S  is  normally  held  in  mid  or  inoperative  posi- 
tion by  the  spring  plungers  at  the  lower  end  of  the  arm  P.  The  gears 
are  driven  continuously  (so  long  as  the  spindle  is  running  ahead),  by 
the  double  gear  Q  on  the  sleeve  above ;  the  clutch  connecting  the 
driving  gear  to  the  spindle  end  is  so  formed,  however,  as  to  be  in- 
operative if  the  spindle  is  reversed,  thus  making  it  impossible  to  en- 
gage the  feed  accidentally  before  the  spindle  is  again  started  ahead. 

Taken  altogether  this  mechanism  represents  the  latest  and  best 
development  in  its  line  for  the  purposes  intended,  and  is  in  keeping 
with  the  usual  practice  of  this  company  of  careful  designing  and 
good,  practical  construction. 

The  Gisholt  turret  lathe  occupies,  a  somewhat  different  field 
than  that  usually  covered  by  the  other  manufacturers  of  turret 
machinery,  in  that  the  machines  are  much  larger  and  heavier  and 
of  much  greater  capacity,  handling  very  large  and  heavy  work. 
While  there  are  none  of  the  other  builders  who  make  a  turret  lathe 
of  much  over  30-inch  swing,  the  Gisholt  lathe  is  built  as  large  as 
41 J  inches,  this  largest  size  weighing  about  eight  tons,  while  there 
are  very  few  of  those  of  other  builders  weighing  more  than  one  half 
as  much. 

Figure  295  shows  this  machine  swinging  41 J  inches  over  the 
bed.  As  will  be  seen,  all  the  parts  are  very  massive  and  calcu- 
lated to  withstand  the  heaviest  strains  to  which  a  machine  of  this 
type  could  possibly  be  subjected. 

The  bed  reaches  to  the  floor  (or  properly  to  a  well  built  founda- 
tion raised  slightly  above  the  floor,  upon  which  a  machine  of  such 


386 


MODERN  LAJHE  PRACTICE 


weight  should  always  be  placed),  and  has  the  head-stock  cast  in 
one  piece  with  it  so. that  the  greatest  amount  of  rigidity  maybe 
preserved.  The  housings  carrying  the  boxes  for  the  main  spindle 

are  heavy  and  of  ample 
width  and  are  three  in  num- 
ber, giving  all  necessary  sup- 
port to  the  spindle.  The 
back  gears  are  placed  over 
the  spindle  and  out  of  the 
way,  making  the  machine 
considerably  narrower  at  this 
point  than  if  they  were 
placed  in  the  rear,  as  is 
usually  the  case.  They  are 
of  coarse  pitch  and  wide  face, 
giving  ample  power  for  all 
occasions. 

The  wearing  surfaces 
throughout  are  made  very 
large,  all  sliding  surfaces 
being  scraped  to  standard 
surface  plates,  and  all  spin- 
dles, arbors,  etc.,  are  finished 
by  grinding  on  dead  centers. 
The  head-stock  is  friction 
back  geared,  and  is  also  pro- 
vided with  an  extra  power- 
ful back  gear  for  doing  the 
heaviest  class  of  work  for 
which  the  machine  is 
adapted.  The  spindle  is 
made  of  forged  steel  and 
runs  in  reamed  and  scraped  bronze  boxes. 

The  turret  is  hexagonal  and  very  large,  in  order  that  heavy  tools 
may  be  rigidly  secured  to  it.  It  slides  directly  on  the  ways  of  the 
machine  and  hence  has  the  full  traverse  of  the  bed.  This  permits 
of  the  use  of  long  boring  bars,  the  outer  ends  of  which  may  be  sup- 
ported in  a  bushing  in  the  chuck. 


REGULAR  TURRET  LATHES  387 

The  carriage  is  provided  with  a  turret  tool-post  carrying  four 
tools,  any  one  of  which  may  be  instantly  brought  into  position  for 
cutting.  These  tools  are  independently  adjustable  as  to  height. 
The  cross  feed  has  micrometer  index  reading  1-1000  of  an  inch. 
Power  cross  feed  and  taper  attachments  are  provided  if  desired. 
For  each  tool  in  the  tool-post  and  for  each  face  of  the  turret  feed 
and  dead  stops,  independently  adjustable,  are  provided,  by  means 
of  which  the  feed  may  be  thrown  out  automatically  at  any  desired 
point.  The  feed  works  are  entirely  novel  and  permit  of  four  changes 
of  feed  being  instantly  obtained,  either  from  the  end  of  the  machine 
or  from  the  turret  slide.  The  feed  is  also  instantly  reversible. 

The  four  tools  which  may  be  carried  in  the  carriage  tool-holder 
are  held  by  means  of  a  large  square  plate,  forced  down  by  a  heavy 
screw  in  its  center.  The  tools  are  placed  under  the  edges  and  parallel 
to  them  and  brought  into  active  position  by  the  entire  tool-holder 
top,  swiveling  turret-like  upon  a  central  pivot,  when  raised  to 
the  proper  position  for  that  purpose.  Stops,  independently  ad- 
justable, are  arranged  for  each  of  these  tools,  both  for  lateral  and 
cross  feeds. 

Turret  stops  are  arranged  at  the  rear  of  the  machine  and  may 
be  severally  brought  into  working  position  by  rotating  the  cylin- 
drical carrier.  They  are,  of  course,  independently  adjustable. 

In  Fig.  296  is  given  a  view  of  the  top  of  the  machine,  which  will 
serve  to  show  the  various  operative  parts  of  the  turret  and  its  stops, 
the  revolving  tool-holder  on  the  carriage,  and  the  taper  attachment, 
much  more  clearly  than  is  shown  in  the  front  view  in  Fig.  295,  and 
on  a  much  larger  scale. 

This  description  might  be  much  more  elaborate  but  the  machine 
is  quite  well  known  among  practical  shop  men  and  those  having 
any  special  connection  with  this  branch  of  machine  business,  and 
further  details  do  not  seem  necessary. 

Pond  tools  are  considered  good  tools  and  are  usually  designed 
heavy  enough  and  strong  enough  to  stand  the  strain  of  any  work 
that  the  machine  may  be  called  upon  to  do.  While  this  remark 
applies  to  a  great  extent  to  all  Pond  tools,  it  is  particularly  applicable 
to  the  Pond  rigid  turret  lathe,  represented  in  Fig.  297,  which  well 
illustrates  its  massive  construction.  This  is  particularly  true  of 
the  tool  carriage  and  of  the  saddle  which  supports  the  turret,  as 


388 


MODERN   LATHE  PRACTICE 


well  as  the  bed,  which  has  the  supporting  legs  cast  with  it.  Its 
design  is  such  as  to  furnish  the  best  resistance  and  support  for  both 
the  strain  of  weight  and  of  torsion. 


FIG.  296.  —  Top  View  of  Gisholt  Turret  Lathe. 

The  swing  over  the  carriage  is  almost  as  great  as  that  over  the 
ways,  which  permits  the  use  of  tool-post  tools  directly  behind  the 


FIG.  297.  —  The  Pond  Rigid  Turret  Lathe. 

work,  and  also  allows  the  carriage  to  be  run  behind  the  chuck  so 
that  the  turret  may  be  brought  up  close  to  the  chuck.  Short, 
rigid  tools  with  practically  no  overhang  and  short  boring  bars  can 


REGULAR  TURRET  LATHES 


389 


therefore  be  used.  In  no  other  machine  is  this  feature  available. 
The  design  of  the  turret  provides  for  six  faces,  three  of  which  are 
of  extra  width,  permitting  the  heaviest  facing,  multiple-turning,  and 
forming  tools  to  be  rigidly  attached. 

This  turret  is  illustrated  in  plan  in  Fig.  298  and  in  elevation  in 
Fig.  299,  showing  the  narrow 
faces  at  A,  A,  A,  in  both  fig- 
ures and  the  wide  faces  B,  B,  B. 
In  the  use  of  a  tool  held  upon 
a  shank  it  is  obvious  that  the 
width  of  the  face  A  is  ample,  as 
all  that  is  necessary  is  sufficient 
strength  around  the  tool-hole 
D,  which  is  provided  for  in  the 
square  surface  at  A.  In  the 
case  of  large  fixtures  such  as 
the  inserted  blade  reamer  for 
a  conical  hole  shown  at  the 
front  of  the  turret  in  Fig.  297,  the  very  wide  face,  provided  with  a 
groove  across  the  center  into  which  a  rib  on  the  tool  base  fits,  and 
the  two  T-slots  for  the  four  bolts  securing  it  to  the  turret,  are 
manifestly  very  valuable  in  holding  the  tool  stiff  and  rigid,  and 
doubtless  suggested  the  name  of  " rigid  turret,"  as  there  is  every 
reason  to  assume  such  condition  from  the  excellent  design. 

The  turret  is  semi-automatic  in  its  movements,  the  rapid  forward 
and  return  movement  and  its  rotation  being  controlled  by  one 

lever.  It  is  indexed  by  worm 
and  worm-wheel,  centered  by 
taper  tool-steel  locking  pin,  and 
clamped  automatically  by  wide 
clamp  rings  having  bearing  a  on 
its  entire  diameter,  thus  insuring 
both  accuracy  and  rigidity.  It 


FIG.  298.  —  Plan  of  the  Turret  of  the 
Pond  Rigid  Turret  Lathe. 


FIG.  299.  —  Elevation  of  the  Turret  of 
the  Pond  Rigid  Turret  Lathe. 


is  arranged  with  hand  wheel  for  operation  by  hand  if  desired. 

Separate  feed-screws  are  provided  for  turret  and  carriage,  giving 
instantaneously  six  different  feeds  with  same  change-gears.  Any 
feed  available  may  be  used  on  both  the  turret  and  cross  carriages 
at  the  same  time. 


390  MODERN  LATHE  PRACTICE 

The  spindle  bearings  are  of  very  large  diameter  and  the  hole 
in  the  spindle  is  4J  inches  in  diameter,  counterbored  to  5J  inches 
in  diameter,  18  inches  in  depth,  so  as  to  permit  boring  bars  with 
both  roughing  and  finishing  cutters  to  be  used;  the  roughing  cutter 
being  inside  the  spindle  when  the  finishing  cutter  is  at  work.  Head- 
stock  has  self-oiling  bronze  bearings  and  a  two-step  cone,  providing 
for  a  very  wide  belt. 

A  complete  line  of  standard  tools  is  furnished  with  these 
machines  for  boring,  facing,  and  turning.  The  firm  has  a  depart- 
ment solely  for  this  purpose,  making  a  specialty  of  designing  and 
furnishing  box  tools  and  dies  for  any  work  that  can  be  handled  on 
a  turret  lathe,  and  adapted  to  this  machine  and  other  machines 
of  its  class. 

It  will  be  noticed  by  reference  to  Fig.  297  that  the  changes  of 
speed  in  the  head-stock  are  effected  by  a  single  lever;  the  changes 
of  feed  by  three  levers  and  two  index  arms  giving  a  great  variety 
of  feeds  and  adapting  the  machine  to  work  on  all  kinds  of  metals 
and  all  diameters  and  forms  having  a  circular  cross  section. 

The  general  dimensions  and  capacities  of  the  machine  are  as 
follows:  swing  over  the  V's,  28  inches;  over  the  cross-slide,  24  J 
inches;  hole  in  spindle,  4J  and  counterbored  to  5J  inches  for  a 
depth  of  18  inches  from  the  front  of  the  spindle.  This  machine  will 
take  in  a  bar  4J  inches  in  diameter.  The  spindle  bearings  are: 
front  bearing,  8x9  inches;  rear  bearing,  5J  x  6  inches.  All  threads 
from  \  to  64  per  inch  can  be  cut.  The  spindle  speeds  are  twenty  in 
number,  and  from  1J  to  182  revolutions  per  minute  in  regular  geo- 
metrical progression.  The  gearing  ratios  for  the  head-stock  are 
respectively  3i  to  1,  8}  to  1,  22  to  1,  and  57  to  1. 

The  tool-holding  holes  in  the  turret  are  3  inches  in  diameter. 
The  distance  from  face  of  chuck  to  face  of  turret  when  at  its  ex- 
treme position  is  5  feet  4  inches.  The  travel  of  the  turret  is  5  feet 
and  its  speed  is  25  feet  per  minute.  The  cross  travel  of  the  car- 
riage is  36  inches,  which  is  very  liberal.  The  turret  tool-post  on 
the  carriage  has  four  tool  positions. 

The  length  of  the  machine  over  all  is  15  feet  11 J  inches,  and  its 
width  5  feet  3  inches.  The  machine  complete  weighs  12,500  pounds, 
a  very  liberal  weight  for  a  machine  of  the  capacity  of  this  one. 


CHAPTER  XXI 

SPECIAL  TURRET  LATHES 

The  R.  K.  Le  Blond  triple-geared  turret  lathe.  General  description.  The 
Springfield  Machine  Tool  Company's  24-inch  engine  lathe  with  a  turret 
on  the  bed.  Its  special  features.  Its  general  dimensions.  Its  design 
and  capacity.  Turret  lathe  for  brass  work  built  by  the  Dreses  Machine 
Tool  Company.  Its  general  description.  .Special  features  and  con- 
struction. A  combination  turret  lathe  built  by  the  R.  K.  Le  Blond 
Machine  Tool  Company.  A  useful  machine  with  many  good  features. 
A  15-inch  swing  brass  forming  lathe  built  by  the  Dreses  Machine  Tool 
Company.  Its  distinguishing  features.  Le  Blond  Machine  Tool  Com- 
pany's plain  turret  lathe.  Plainness  and  simplicity  its  strongest  points. 
General  dimensions.  The  Springfield  Machine  Tool  Company's  hand 
turret  lathe.  A  modification  of  their  18-inch  swing  engine  lathe.  The 
Pratt  &  Whitney  monitor  lathe  or  turret-head  chucking  lathe.  Its  gen- 
eral features  and  construction. 

THE  R.  K.  Le  Blond  Machine  Tool  Company  build  a  line  of 
well  designed  and  substantial  turret  lathes,  a  representative  of 
which  is  shown  in  Fig.  300,  which  is  of  a  31-inch  swing,  triple-geared 
machine  with  double  back  gears  and  a  friction  device,  and  is  driven 


FIG.  300.  —  31-inch  Triple  Geared  Turret  Lathe,  built  by  the 
R.  K.  Le  Blond  Machine  Tool  Company. 
391 


392  MODERN  LATHE  PRACTICE 

from  a  triple-speeded  friction  countershaft,  by  means  of  which 
fifteen  speeds  may  be  had  without  changing  a  belt,  thus  adapting 
it  to  a  great  range  of  work  requiring  different  speeds  in  order  to 
do  the  work  with  the  maximum  degree  of  efficiency. 

Special  attention  has  evidently  been  given  to  the  design,  so  as 
to  have  it  very  strong  and  rigid  in  all  parts  which  support  the  work- 
ing members  so  as  to  afford  an  ample  protection  against  vibrations 
when  taking  heavy  cuts.  The  head-stock  is  unusually  large  and 
massive. 

It  is  back  geared  55  to  1,  so  that  it  has  enormous  power  for  form- 
ing and  facing  cuts.  The  turret  has  a  double  bearing  on  the  slide, 
making  it  perfectly  rigid.  It  is  locked  with  their  patented  locking 
pin,  having  a  bearing  on  both  sides  of  the  locking  ring.  All  wear 
can  be  taken  up  between  the  turret  and  stem  by  means  of  a  taper 
bushing.  The  carriage  is  very  heavy,  gibbed  both  back  and  front, 
and  the  rack  pinion  is  supported  on  both  sides  of  the  rack. 

This  lathe  is  especially  fitted  for  box  or  forming  tools,  and  will 
work  a  nest  of  roughing  tools  to  good  advantage.  Changes  of 
feed  can  be  had  instantly  by  the  use  of  the  lever  shown  on  the  bed ; 
and,  with  half  nuts  in  the  apron,  and  any  tapping  work  can  be  done 
with  positive  lead  from  the  screw.  A  specially  strong  chuck  is  fur- 
nished having,  in  addition  to  the  hardened  jaws,  a  set  of  soft  ones  to 
be  used  for  the  second  operation,  so  as  to  secure  perfectly  concentric 
work,  which  is  frequently  difficult,  particularly  when  the  limits  of 
measurement  and  the  exact  running  of  the  work  are  important 
conditions. 

It  will  be  noticed  that  the  feed  gears  are  of  broad  face  and  well 
adapted  to  heavy  work  and  that  the  lathe  carries  a  very  heavy  and 
strong  chuck,  which  is  all-important  when  heavy  cuts  are  to  be 
made  as  well  as  when  the  work  itself  consists  of  large  and  heavy 
pieces.  It  is  particularly  well  adapted  to  machining  forging  up  to 
the  limits  of  its  swing  and  of  rough  outline,  which  usually  prove 
very  trying  to  any  lathe  containing  any  inherent  weakness  of  con- 
struction. 

As  an  example  of  the  second  class,  the  24-inch  swing  engine 
lathe,  built  by  the  Springfield  Machine  Tool  Company,  is  shown  in 
Fig.  301.  In  this  case  it  will  be  seen  that  the  carriage  remains  on 
the  lathe  as  usual  and  may  be  used  in  conjunction  with  the  turret 


SPECIAL  TURRET  LATHES 


393 


which  is  pivoted  to  a  slide,  supported  by  a  bed  or  saddle  which  rests 
upon  the  V's  and  is  fixed  to  the  bed  in  the  usual  manner. 

While  turrets  thus  applied  to  an  engine  lathe  are  usually 
equipped  for  hand  feed  only,  there  is  a  device  furnished  with  them 
by  some  builders,  by  the  use  of  which  a  power  feed  is  provided. 
This  is  the  case  with  the  lathe  here  shown. 

The  turret  slide  is  supplied  with  variable  power  feed  and  auto- 
matic stop,  which  in  no  manner  interferes  with  the  usual  engine 
lathe  feeds  and  screw-cutting  mechanism,  each  being  entirely  inde- 
pendent of  the  other,  and  can  be  used  separately  or  collectively 
as  the  work  demands.  Therefore,  should  conditions  exist  where 
the  same  lathe  is  to  be  used  for  turning  work  between  centers  as 
well  as  when  held  in  chuck  or  face-plate,  the  tail-stock  can  be  fur- 


FIG.  301.  —  24-inch    Swing  Engine  Lathe  with  Turret  on  the  Bed,  built 
by  the  Springfield  Machine  Tool  Company. 

nished  with  which  the  turret  interchanges,  and  either  a  regular 
complete  engine  lathe  is  at  hand  or  a  modern  turret  lathe. 

The  turrets  are  all  furnished  with  power  feed,  but  are  made  to 
revolve  automatically  or  by  hand  to  suit  the  user. 

The  details  are  constructed  with  great  care.  The  index  ring  is 
of  large  diameter  and  made  of  tool  steel.  The  locking  plunger  is 
also  made  of  tool  steel  slides  between  large  bearings,  with  provision 
for  adjustment  to  take  up  wear. 

All  the  parts  pertaining  to  the  automatic  revolving  mechanism 
of  turret  are  also  made  of  tool  steel  and  hardened. 

Feeds  are  engaged  and  disengaged  by  levers  conveniently  placed 
in  front  of  the  pilot  wheel. 


394  MODERN  LATHE  PRACTICE 

Although  these  turrets  are  of  massive  proportions,  and  possess 
rigidity  to  an  unusual  degree,  they  are  very  conveniently  handled, 
an  important  factor  towards  the  ends  sought. 

Some  of  the  dimensions  of  these  turrets  are  as  follows:  width 
across  flats,  12 J  inches;  diameter  of  holes  for  holding  tools,  2J  inches; 
length  of  the  top  slide  upon  which  the  turret  is  pivoted,  46  inches; 
width  of  the  bearing  surface,  11  inches;  length  of  bottom  slide,  or 
saddle,  30  inches;  width  of  bottom  slide,  11  inches;  extreme  dis- 
tance between  lathe  spindle  and  turret  face  on  a  lathe  with  a  10-foot 
bed,  42  inches;  weight  of  turret,  1,200  pounds. 

These  figures  will  give  a  good  idea  of  the  substantial  design  of 
this  device,  which  was  evidently  intended  for  heavy  work  and  hard 
usage.  It  is  very  important  that  all  parts  of  a  turret,  of  whatever 
kind  of  type  and  for  whatever  purpose,  should  be  strong,  rigid,  and 
well  fitted.  If  not  of  sufficient  weight  to  give  it  the  necessary 
strength  it  will  fail  when  put  to  the  actual  test  of  hard  work.  If 
not  of  sufficient  rigidity  the  tools  will  " chatter"  and  either  seriously 
mar  or  spoil  the  work.  If  all  the  parts  are  not  well  fitted  the  tools 
will  not  "line  up"  with  the  head-stock  spindle,  and  as  a  consequence 
true  work  cannot  be  done  in  the  machine.  It  may  be  stated  as  a 
practical  fact  that  in  turrets  built  by  the  best  manufacturers  it  is  not 
usual  to  find  the  entire  six  holes  lining  up  perfectly  with  the  head- 
stock  spindle.  While  the  present  machines  of  this  type  are  far 
ahead  of  those  built  a  few  years  ago,  in  these  respects,  the  prac- 
tical shop  man  will  be  fairly  well  satisfied  with  a  turret  if  he  finds 
but  two  of  the  holes  "dead  true,"  two  more  near  enough  true  for 
the  usual  class  of  work,  and  the  remaining  two  considerably  out  of 
true.  And  this  will  generally  be  the  case  even  though  the  "finish 
boring"  of  these  holes  is  done  with  a  tool  carried  by  the  head-stock 
spindle  in  the  lathe  that  the  turret  is  fitted  up  for.  To  the  young 
machinist  this  may  seem  strange,  but  it  is  nevertheless  true,  and 
true  of  probably  a  large  majority  of  turret  machines  of  the  present 
day. 

A  very  complete  turret  lathe  for  working  brass  and  other  similar 
metals  is  built  by  the  Dreses  Machine  Tool  Company.  It  is  shown 
in  Fig.  302,  and  is  known  as  a  15-inch  friction  back  geared  brass 
turret  lathe,  and  is  provided  with  a  special  chuck,  cutting-off  slide 
and  a  slide-rest. 


SPECIAL  TURRET    LATHES 


395 


The  bed  is  of  the  box  pattern  with  a  dovetail  top,  which  pro- 
vides the  best  means  for  keeping  alignment  and  for  quick  and  firm 
gripping  of  the  turret  and  cut-off  rest.  It  is  supported  on  the 
three- point  principle  to  avoid  springing  and  getting  out  of  align- 
ment through  careless  setting  up  or  settling  of  floors  and  foun- 
dations. The  top  is  provided  with  holes  for  the  oil  and  chips  to 
drop  through. 

The  head-stock  on  the  smaller  machines  is  cast  in  one  piece  with 
the  bed.  In  this  machine  it  is  attached  to  the  bed  by  gibs  and 
bolts.  The  housings  are  provided  for  either  phosphor  bronze  or 
babbitt  metal  bearings. 


FIG.  302.  —  15-inch  Friction  Back  Geared  Brass  Turret  Lathe,  with  Special 
Chuck,  Cutting-off  Slide  and  Slide-Rest,  built  by  the  Dreses  Machine 
Tool  Company. 

The  friction  clutch  back  gear  is  of  a  new  design,  very  simple  in 
operation  and  positive  in  action.  The  wear  is  taken  up  by  a  screw 
driver  from  the  outside,  without  even  removing  the  cover. 

The  spindle  is  of  special  hammered  crucible  steel.  The  bear- 
ings are  ground  and  run  in  phosphor  bronze  boxes  with  special 
means  for  oiling  and  taking  up  the  wear. 

The  turret  revolves  automatically  on  a  ground  steel  stem  with 
special  device  for  taking  up  the  wear.  It  is  provided  with  a  set- 
over  device.  The  top  slide  can  be  operated  either  by  the  crank 
and  screw  shown  at  the  rear  end,  or  by  the  capstan  levers  in  the 
usual  manner.  One  of  the  capstan  handles  is  provided  with  a  short 
handle  at  right  angles  with  it  for  convenience  in  quick  operations. 


396  MODERN  LATHE  PRACTICE 

The  entire  capstan  wheel  may  be  removed  and  a  crank  substituted 
when  quick  operations  are  constantly  required. 

The  longitudinal  and  cross-feed  stop  screws  are  located  in  easily 
accessible  places.  The  base  slide  is  clamped  to  the  bed  by  a  single 
handle  and  the  operation  of  clamping  is  by  a  single  motion. 

The  turret  locking  bolt  withdraws  by  the  return  stroke  of  the 
top  slide,  so  that  the  operator  needs  only  to  revolve  the  turret. 
This  is  equally  effective  as  a  full  automatic  turret,  but  less  costly 
and  complicated. 

The  index  ring  and  key  are  of  hardened  steel  and  ground.  The 
square  locking  bolt  is  provided  with  an  adjustable  taper  gib,  and 
a  coil  spring  for  actuating  it. 

The  cutting-off  slide  is  extra  heavy  and  is  provided  with  an 
independent  stop  for  both  front  and  rear  tools.  It  has  both  a  screw 
and  crank  wheel  feed  and  a  lever  feed,  either  of  which  may  be  used 
as  occasion  may  require. 

The  slide-rest  is  of  much  better  design  and  construction  than 
is  common  in  similar  work  and  is  a  very  useful  addition  to  the  lathe, 
increasing  its  capacity  in  handling  work  of  complicated  nature, 
as  by  its  use  another  series  of  cuts  may  be  made  without  removing 
the  work  from  the  chuck. 

The  special  chuck  is  so  arranged  that  the  work  may  be  gripped 
or  released  while  the  machine  is  running,  thus  avoiding  the  neces- 
sity of  stopping  to  feed  the  bar  in  every  time  a  piece  of  work  is  cut 
from  the  bar. 

The  feed  is  a  positive  geared  device  that  should  do  the  work 
well  and  efficiently. 

Taken  altogether  the  lathe  is  well  designed  and  has  been  pro- 
vided with  many  very  useful  devices  that  no  doubt  prove  con- 
venient and  effective  in  practical  work.  The  special  forming  slide 
located  next  to  the  turret  may,  of  course,  be  located  at  any  point 
in  relation  to  the  usual  cutting-off  slide  or  the  slide-rest  that  may 
be  desired  in  order  to  properly  perform  the  work  in  hand.  Either 
of  these  adjuncts  may  be  removed  when  not  required  for  the  piece 
to  be  machined,  or  all  may  be  used  upon  a  long  or  complicated  job 
when  needed. 

A  combination  turret  lathe  built  by  the  R.  K.  Le  Blond  Machine 
Tool  Company  is  shown  in  Fig.  303.  The  head-stock  and  its  appen- 


SPECIAL  TURRET  LATHES 


397 


dages  are  the  same  as  those  shown  in  Fig.  300,  and  the  bed  and 
cabinets  supporting  it  are  the  same.  The  turret  and  carriage 
arrangements,  however,  are  quite  different  and  adapted  to  a  much 
larger  range  of  work. 

The  carriage  is  fitted  with  a  turret  tool-post  which  will  carry 
four  tools  under  the  massive  top  plate  shown,  and  which  are  securely 
fastened  by  the  set-screws  through  it,  thus  materially  increasing  its 
capacity  for  different  cuts  on  the  same  piece  of  work.  A  binding 
lever  on  its  top  secures  the  tool  clamp  in  any  desired  position. 


FIG.  303.  —  Combination  Turret  Lathe,  built  by  the  R.  K.  Le  Blond 

Machine  Tool  Company. 

The  turret  is  very  heavy  and  well  supported  by  the  turret  slide, 
upon  which  it  is  pivoted,  and  a  long  base  slide  or  saddle.  It  is  run 
forward  and  back  by  a  capstan  or  pilot  wheel  with  long  levers  giving 
ample  hand  power. 

The  turret  can  be  connected  with  the  carriage  so  as  to  be  used 
for  thread  cutting  and  for  tapping,  as  it  thus  connects  positively 
with  the  lead  screw  by  way  of  the  apron.  This  feature  is  valuable 
in  many  respects. 

In  addition  to  the  above  convenience  it  has  its  own  automatic 
feed,  which  has  an  unusually  long  run.  As  the  turret  has  six  large 
flat  faces,  each  tapped  with  four  holes  in  addition  to  the  central  hole 
for  holding  tools,  it  is  well  adapted  for  carrying  large  box  tools, 
facing  tools,  or  farming  tools  for  special  work. 

The  turret  has  the  usual  stops  for  regulating  the  length  of  the 
cuts,  and  a  heavy  binding  nut  lever  for  holding  it  firmly  in  any 
desired  position. 


398 


MODERN  LATHE   PRACTICE 


It  is  altogether  an  exceedingly  useful  machine,  combining  many 
practical  features,  great  weight,  strength  and  rigidity,  and  conse- 
quently capable  of  performing  very  heavy  work. 

The  turret-forming  lathe  is  a  machine  that  is  very  useful  on  a 
variety  of  work  in  which  complicated  outlines  occur  in  a  piece  of 
circular  cross  section,  and  in  which  a  large  number  of  pieces  of 
exactly  the  same  design  and  contour  are  required.  In  handling 
brass  work  of  this  variety,  what  is  known  as  the  forming  slide,  verti- 


^       -* 

FIG.  304.  — 15-inch  Forming  Turret  Lathe  with  Automatic  Chuck,  built  by 
the  Dreses  Machine  Tool  Company. 

cal  forming  rest,  etc.,  is  found  very  useful,  doing  the  work  upon 
soft  metals  that  the  very  heavy  rest  with  its  horizontal  forming 
tools  do  for  the  harder  metals,  as  iron  and  steel. 

In  Fig.  304  is  shown  a  15-inch  swing  brass  forming  lathe,  with 
automatic  chuck.  It  is  built  by  the  Dreses  Machine  Tool  Company. 

The  distinguishing  feature  of  the  machine  is  the  forming  slide, 
which  consists  of  a  base  securely  clamped  to  the  bed  and  support- 
ing a  horizontal  slide  fitted  in  a  dovetail  and  moved  by  a  feed  or 
adjusting  screw.  Upon  the  top  of  this  slide  is  secured  an  upright 


SPECIAL  TURRET  LATHES  399 

having  formed  upon  it  a  dovetail,  and  being  adapted  to  swivel 
within  a  small  arc.  Upon  the  dovetail  on  this  upright  is  fitted 
another  slide  which  is  moved  by  means  of  a  rack,  pinion,  and 
lever.  This  latter  carries  the  forming  tool-holder,  which  is  also 
capable  of  being  tilted  slightly  and  properly  clamped  when  it  is 
adjusted  to  the  right  position. 

In  front  of  the  slide  to  which  the  upright  is  attached  is  placed 
an  auxiliary  small  slide,  provided  with  a  tool-post  and  operated 
by  the  handle  shown  at  the  left.  This  slide  is  for  use  in  cutting- 
off  and  for  other  final  operations. 

For  the  purpose  of  adjusting  the  forming  tool  to  the  chucked 

casting  which  is  to  be  machined,  the  entire  mechanism  can  be 

moved  longitudinally  on  the  bed  by  means  of  the  rack  and  pinion. 

A  tightening  clamp  is  provided  by  which  the  forming  rest  may  be 

clamped  or  released  instantly. 

An  automatic  chuck  is  provided  in  which  work  may  be  gripped 
and  released  without  stopping  the  machine.  This  is  very  con- 
venient when  bar  stock  is  used. 

While  the  machine,  as  shown,  is  without  back  gears,  the  manu- 
facturers build  them  with  this  additional  means  of  increasing  the 
power  when  such  is  required. 

The  countershaft  is  of  the  double  friction  type,  whereby  six- 
spindle  speeds  are  obtained. 

The  plan  of  adding  the  forming  slide  feature  to  the  turret  lathe 
is  of  much  interest  in  manufacture,  since  it  increases  very  much  the 
range  of  the  work  for  which  the  machine  may  be  used,  and  with 
this  forming  slide  so  designed  as  to  make  it  compound  in  its  action, 
and  including  also  the  cutting-off  tool-post,  its  usefulness  is  still 
further  increased,  making  the  machine  as  a  whole  a  valuable  one 
on  all  light  machine  operations  for  any  work  within  its  range  and 
capacity. 

One  of  the  plainest  types  of  turret  lathes  is  built  by  the  R.  K. 
Le  Blond  Machine  Tool  Company  and  is  shown  in  Fig.  305.  Its 
plainness  and  simplicity  are  its  strongest  points.  While  its  initial 
cost  is  reduced  to  a  minimum,  its  capacity  for  handling  a  variety  of 
different  kinds  of  work  is  not  correspondingly  lessened,  as  it  is  well 
adapted  to  the  lighter  kinds  of  steel  work,  to  cast  iron  of  consider- 
able dimensions,  and  to  work  of  brass  and  other  softer  metals.  Not- 


400 


MODERN   LATHE   PRACTICE 


withstanding  the  fact  that  this  limits  its  range  of  work  somewhat, 
it  is  a  machine  of  much  practical  usefulness  as  a  great  variety  of 
light  manufacturing  comes  well  within  its  range,  and  it  can  be  done 
as  well  and  as  rapidly  as  on  a  much  more  complicated  and  expen- 
sive machine. 

The  head-stock  is  long  and  heavy,  supporting  boxes  for  the 
spindle  journals  of  ample  dimensions.  The  spindle  is  hollow  and 
of  large  size  so  that  bar  stock  may  be  worked  up.  The  end  thrust 
is  taken  by  ball  bearings  which  minimize  friction.  The  driving- 
cone  has  four  steps  and  is  adapted  for  an  extra  wide  belt.  The 
countershaft  is  of  the  double  friction  type,  thus  giving  eight  speeds. 


FIG.  305.  —  16-inch  Plain  Turret  Lathe,  built  by  the  R.  K.  Le  Blond 

Machine  Tool  Company. 

The  turret  is  very  simple,  having  as  few  parts  as  possible  in  their 
construction.  The  turret  proper  revolves  automatically,  and  when 
the  top  slide  is  flush  with  the  bottom  it  can  be  revolved  freely  by 
hand  and  any  desired  tool  brought  quickly  into  position  for  work. 
The  indexing  ring  is  of  large  diameter  and  made  of  tool  steel, 
hardened  and  ground,  as  is  also  the  locking  plunger,  which  auto- 
matically adjusts  itself  for  wear.  The  wear  between  the  turret  and 
the  stem  upon  which  it  is  pivoted  is  taken  up  by  an  adjustable  taper 
bushing. 


SPECIAL  TURRET  LATHES 


401 


The  top  slide  is  square  gibbed  and  adjusted  by  a  taper  gib.  The 
turret  base  is  securely  clamped  in  any  position  on  the  bed  by 
two  eccentric  clamps  operated  by  a  wrench  from  the  front  of  the 
turret. 

The  power  feed  is  driven  by  a  belt  upon  the  four-step  feed  cones. 
It  is  positive  in  its  action  as  a  belt  feed  can  be,  and  is  engaged  by 
a  lever  at  the  front  of  the  turret  and  can  be  tripped  to  a  line  in  any 
position  by  an  adjustable  stop. 

The  lathe  shown  is  of  16-inch  swing  and  has  a  circular  turret 
8J  inches  in  diameter.  It  is  drilled  with  six  holes  1}  inches  in 
diameter.  The  automatic  feed  is  9  inches.  It  has  a  deep  and  strong 
bed  and  is  in  its  design  a  very  substantial  machine. 


FIG.  306.  —  18-inch  Engine  Lathe,  with  Turret  on  Special  Carriage, 
built  by  the  Springfield  Machine  Tool  Company. 

As  an  example  of  the  simplest  form  of  a  turret  lathe  with  a  hand 
turret  mounted  upon  the  carriage,  the  one  shown  in  Fig.  306  is 
given.  It  is  an  18-inch  swing  engine  lathe  built  by  the  Spring- 
field Machine  Tool  Company,  and  in  this  particular  case  a  special 
carriage  is  shown,  although  it  is  very  little  different  from  the  reg- 
ular carriage  upon  which  the  turret  may  be  as  readily  mounted. 

In  this  case  no  cutting-off  slide  is  provided,  although  one  may 
be  readily  attached  by  fitting  it  to  the  V's  and  gibbing  it  to  the 
bed  in  the  same  manner  as  the  carriage  is  held  to  the  bed. 


402  MODERN  LATHE  PRACTICE 

Some  of  the  special  features  and  dimensions  of  this  turret  lathe 
are  as  follows,  the  information  for  the  same  being  derived  direct 
from  the  manufacturers. 

Thjs  lathe  is  a  modification  of  the  standard  18-inch  engine  lathe, 
to  serve  the  purpose  of  a  heavy  turret  lathe,  a  type  which  is  becom- 
ing deservedly  popular  with  the  manufacturers  of  machinery. 
With  the  exception  of  the  turret  on  the  carriage  and  the  turret  slide, 
the  regular  design  of  the  engine  lathe  has  been  maintained. 

The  carriage  is  very  heavy,  gibbed  to  the  outside  of  the  bed,  both 
front  and  back,  and  is  fitted  with  a  turret  slide  of  unusual  propor- 
tions —  10  inches  in  width  and  16  inches  in  length,  upon  which  the 
turret  proper  revolves. 

The  turret  is  hexagonal  in  form  and  10J  inches  in  width  across 
the  flats.  The  holes  in  the  same  may  be  as  large  as  2  inches  in 
diameter,  and  the  construction  is  such  that  a  bar  may  be  passed 
entirely  through  the  turret.  The  advantages  of  this  arrangement 
are  too  numerous  and  well  understood  to  require  any  further  ex- 
planation. The  index  pin  and  clamping  lever  are  on  the  right  side 
of  the  turret,  and,  although  entirely  out  of  the  way,  very  convenient 
for  manipulation. 

The  lathe  is  provided  with  power  cross  feed,  as  well  as  longi- 
tudinal feed  and  screw-cutting  apparatus,  and  may  be  equipped 
with  taper  attachment  if  desired,  and  hence  can  perform  on  chuck 
or  face  plate  work  all  the  functions  usually  done  with  the  regular 
engine  lathe,  with  the  advantage  of  greatly  increased  production 
within  the  same  period  of  time.  As  a  further  convenience  a  taper 
attachment  is  added. 

This  taper  attachment  is  designed  with  a  view  to  strength  and 
stability,  and  is  attached  to  the  rear  of  the  carriage.  It  will  turn 
tapers  up  to  4  inches  to  the  foot. 

Such  a  lathe  is  an  exceedingly  useful  machine  on  a  great  variety 
of  jobs  continually  occurring  in  the  machine  shop,  particularly 
those  of  which  there  is  a  small  quantity  only  to  be  made.  Many  of 
these  jobs  may  have  a  portion  of  the  work  advantageously  done 
on  this  lathe,  and  the  balance  on  an  engine  lathe,  both  working  in 
conjunction  with  more  efficiency  than  either  would  alone. 

In  Fig.  307  is  shown  an  example  of  what  has  been  spoken  of  as 
a  " monitor"  lathe  or  turret  head  chucking  lathe,  although  it  is 


SPECIAL  TURRET  LATHES 


403 


used  for  many  k'nds  of  work  beside  chucking  single  pieces.     It  is 
of  10-inch  swing  and  built  by  the  Pratt  &  Whitney  Company. 

These  machines  are  used  for  drilling,  boring,  and  reaming  holes 
at  a  much  faster  rate  and  with  more  uniformity  than  similar  work 
can  be  done  on  lathes  formerly  used  for  the  purpose.  They  are 
also  largely  used  to  finish  parts  of  machinery,  cast  or  forged  pieces 
of  irregular  outline  and  circular  cross  section,  when  fitted  with 
the  necessary  tools. 


FIG.  307.  —  10-inch  Monitor  Lathe,  built  by  the 
Pratt  &  Whitney  Company. 

They  have  the  same  construction  as  the  revolving  head  screw 
machines  above  the  bed,  but  are  not  usually  furnished  with  the 
wire  feed  apparatus  for  feeding  wire  or  rods  through  the  chuck 
automatically,  or  provided  with  an  oil  tank,  dripping  device,  etc., 
as  the  work  usually  done  upon  them  does  not  require  the  use  of  oil 
in  cutting.  When  oil  is  required  these  accessories  may  be  readily 
attached. 

The  heads  have  provision  for  vertical  and  horizontal  adjust- 
ment of  the  spindle  in  case  its  alignment  with  the  turret  holes  is 


404  MODERN   LATHE  PRACTICE 

lost  by  wear.  The  spindles  are  made  of  hard,  crucible  steel,  and 
are  provided  with  cylindrical  boxes  lined  with  genuine  babbitt 
metal. 

The  larger  sizes  of  these  machines  are  built  with  back  gears, 
which  render  them  capable  of  doing  much  heavier  work  than  the 
machine  shown  in  the  engraving. 

With  this  machine,  with  its  quick  acting  and  convenient  hand 
lever  for  operating  the  turret,  a  very  large  amount  of  work  can  be 
turned  out  in  a  day;  in  fact,  considering  the  cost  of  the  machine,  it 
is,  for  all  work  within  its  capacity,  frequently  more  efficient  than 
the  larger  sizes  and  more  elaborate  designs  of  this  machine  and 
others  of  the  same  general  type. 

The  lever  by  which  the  turret  slide  is  operated  also  automatically 
effects  the  revolution  of  the  turret  at  the  end  of  the  return  stroke 
and  the  beginning  of  the  next  forward  movement. 

There  is  a  cutting-off  slide  carrying  two  tool-posts,  so  that  a 
front  and  back  tool  may  be  used.  One  of  these  may  be  a  cut  ting- 
off  tool  and  the  other  a  forming  tool,  if  such  a  tool  is  needed.  Thus 
it  is  adapted  to  turning  to  size,  or  several  sizes;  threading  with  a 
die  in  one  of  the  tool-holding  holes  in  the  turret;  drilling,  reaming, 
etc.,  by  the  turret;  and  forming  and  cutting  off  by  the  cut-off  slide, 
making  it  exceedingly  useful  considering  its  simplicity  and  economy. 


CHAPTER  XXII 

ELECTRICALLY  DRIVEN  LATHES 

System  of  electric  drives.  Principal  advantages  of  driving  lathes  by  elec- 
tricity. Group  drive  versus  individual  motor  system.  Individual 
motor  drives  preferable  for  medium  and  large  sized  lathes.  The  Reed 
16-inch  swing  motor-driven  lathe.  The  Lodge  &  Shipley  24-inch  swing 
motor-driven  lathe.  The  Prentice  Brothers  Company's  motor-driven 
lathes.  General  description.  Crocker-Wheeler  motors.  Renold  silent 
chain.  The  Hendey-Norton  lathe  with  elevated  electric  motor  drive. 
Special  features.  A  50-inch  swing  lathe  with  electric  motor  drive  de- 
signed by  the  Author.  Detailed  description  Practical  usefulness. 
Not  strikingly  original,  but  successful. 

ONE  of  the  more  important  developments  of  the  modern  ma- 
chine shop  tools  is  the  electric  drive,  with  which  many  of  them  are 
equipped.  While  the  system  of  driving  by  electric  motors  has 
many  phases,  and  all  of  them  most  interesting  problems,  this  chapter 
will  be  more  particularly  concerned  with  the  question  of  individual 
motors  for  the  machines,  leaving  out  the  question  of  driving  a 
group  of  machines  from  a  "  jack  shaft "  operated  by  a  single  motor, 
and  the  plan  of  driving  line  shafts  in  the  same  manner. 

There  are  many  advantages  in  driving  machines,  particularly 
lathes,  with  individual  motors;  among  them  being: 

First,  the  power,  and  in  case  of  variable  speed  motors  the  speed 
is  directly  under  the  control  of  the  operator; 

Second,  there  is  economy  in  the  use  of  power,  as  none  is  used  to 
drive  "jack  shafts"  or  countershafts; 

Third,  there  is  also  economy  in  the  use  of  power  as  none  is  con- 
sumed except  when  the  lathe  is  in  actual  operation;  and 

Fourth,  the  wear  and  tear  of  belting  is  either  reduced  to  a  mini- 
mum or  eliminated  altogether. 

While  it  may  be  still  an  open  question  whether  the  "group 

405 


406 


MODERN   LATHE   PRACTICE 


drive"  system  or  the  individual  motor  system  is  the  better,  par- 
ticularly for  small  lathes,  there  seems  to  be  no  doubt  of  the  indi- 
vidual motor  system  for  medium  and  large  lathes,  say  from 
24-inch  swing  upwards. 

In  this  chapter,  therefore,  it  is  proposed  to  describe  and  illus- 
trate the  modern  individual  motor  system  as  applied  to  lathes 
made  by  the  American  up-to-date  builder  of  lathes,  and  in  doing 


FIG.  308.  —  16-inch  Swing  Reed  Motor-Driven  Lathe. 


this  to  show  those  put  on  the  market  by  the  more  representative 
concerns  engaged  in  this  business. 

In  Fig.  308  is  shown  a  16-inch  swing  Reed  motor-driven  lathe. 
The  motor  is  one-horse  power,  direct  connected,  with  variable  speed. 
The  motor  and  its  controller  are  built  by  the  General  Electric  Com- 
pany. The  motor  has  a  speed  of  from  500  to  1500  revolutions  per 
minute. 

As  shown  in  the  engraving  the  motor  is  geared  directly  to  the 
main  spindle  by  suitable  gearing  so  that  no  belt  is  required.  This 


ELECTRICALLY  DRIVEN   LATHES 


407 


method  seems  preferable  to  the  plan  of  using  a  short  belt.  The 
noise  of  fast  running  gears,  in  a  device  of  this  kind,  may  be  avoided 
by  introducing  a  rawhide  intermediate  gear  next  to  the  small  steel 
pinion  on  the  motor  shaft,  by  which  means  the  gears  will  run  com- 
paratively quiet  even  at  a  very  high  rate  of  speed  of  the  motor 
shaft. 

The  Lodge  &  Shipley  24-inch  swing  motor-driven  engine  lathe 
is  shown  in  Fig.  309.    This  design  uses  a  short  belt  in  driving  from 


FIG.  309.  —  24-inch  Swing  Lodge  &  Shipley  Motor-Driven  Lathe. 

a  small  two-step  cone  on  the  motor  shaft  to  the  spindle  cone.  The 
motor  is  of  the  variable  speed  type  with  a  speed  variation  of  two  to 
one. 

The  motor  is  mounted  on  an  overhead  bracket  directly  above 
the  head-stock,  pivoted  at  the  rear  to  two  heavy  standards  bolted 
on  to  the  back  of  the  bed,  and  is  connected  to  the  driving  pulley  by 
a  short,  wide  belt,  in  which  sufficient  tension  for  driving  is  obtained 
by  means  of  the  adjusting  screw  with  a  hand  wheel  at  the  front  of 
the  head-stock. 


408  MODERN  LATHE  PRACTICE 

When  this  system  is  used  the  cone  pulley  has  two  steps,  and 
two  sets  of  back  gears  are  provided,  so  that  the  combination  affords 
a  total  of  six  speed  changes,  two  with  the  lathe  out  of  gear  and  two 
with  each  of  the  back  gears  in.  By  varying  the  speed  of  the 
motor,  either  through  the  introduction  of  field  resistance  or  by 
use  of  one  of  the  multiple  voltage  systems,  intermediate 
speeds  in  each  range  are  obtained,  the  number  of  which  depends 
only  on  the  number  of  points  in  the  controller.  With  a  20-point 
controller,  120  distinct  spindle  speeds  are  thus  afforded. 

This  company  also  equip  their  lathes  with  constant  speed 
motors,  for  which  purpose  they  mount  the  motor  at  the  rear  of  the 
head-stock  near  the  floor.  From  a  small  pulley  on  the  motor  shaft 
a  belt  runs  up  to  a  large  pulley  on  a  countershaft  located  directly 
in  the  rear  of  the  head-stock.  This  countershaft  carries  the  usual 
speed  cone,  from  which  a  short  belt  connects  with  the  spindle  cone  in 
the  usual  manner.  The  countershaft  speed  is  from  125  to  200  revo- 
lutions per  minute. 

In  buying  a  motor-driven  lathe,  the  purchaser  has  usually  to 
decide  between  a  direct-connected  and  a  belt-connected  lathe,  and 
between  a  constant  speed  and  a  variable  speed  motor.  The  use 
of  a  constant  speed  motor  direct  geared  to  the  lathe  is  practically 
prohibited,  on  account  of  the  mass  of  gearing  necessary  to  secure 
sufficient  speed  changes. 

This  may  be  obviated  by  using  the  countershaft  as  above 
arranged,  although  it  is  well  known  that  short  belts  are  objection- 
able on  account  of  the  high  tension  that  must  be  maintained  to 
render  them  capable  of  transmitting  the  required  power  to  properly 
operate  the  lathe. 

The  Prentice  Brothers  Company  equip  their  14,  16,  18,  20,  and 
22-inch  swing  engine  lathes  with  a  motor  drive  device  which  is 
shown  in  Fig  310. 

In  this  case  the  motor  is  under  the  bed  and  close  to  the  head 
cabinet.  Eight  changes  of  spindle  speed  are  provided  for  by  means 
of  a  series  of  gearing  located  in  the  head-stock  of  the  lathe.  All 
of  these  speeds  are  available  without  stopping  the  lathe.  The 
gearing  is  so  arranged  that  it  is  impossible  for  the  operator  to  inter- 
lock any  conflicting  ratios  of  gearing.  This  is  an  advantage  that 
i*  greatly  appreciated,  as  it  removes  all  possible  danger  of  break- 


ELECTRICALLY  DRIVEN   LATHES 


409 


age  to  the  gearing  or  the  clutches  in  the  driving  mechanism  of  the 
machine. 

A  mechanical  reverse  is  provided  and  may  be  operated  from 
the  carriage  of  the  lathe  so  that  the  operator  can  start,  stop,  and 
reverse  the  direction  of  the  spindle  without  stopping  the  motor. 
This  is  a  great  saving  of  power  over  the  method  commonly  used, 
that  is,  reversing  the  motor,  stopping  and  starting  the  motor  when 
stopping,  starting,  and  reversing  the  lathe. 

For  operating  this  lathe  the  manufacturers  recommend  a  con- 
stant speed  motor  with  either  direct  or  alternating  current,  although 
a  direct-current  motor,  with  a  variation  allowing  an  increase  of 


FIG.  310.  —  18-inch  Swing  Prentice  Motor-Driven  Lathe. 

50  per  cent  in  the  speed,  can  be  used  to  some  advantage  and  would 
divide  the  steps  of  the  mechanical  speed  variation  into  five  or  six 
additional  changes,  giving  40  or  48  changes  of  speed  in  all. 

In  general  practice,  however,  this  great  number  of  speeds  is 
not  needed.  The  advantages  of  using  a  constant  speed  motor  are 
numerous  beyond  the  matter  of  efficiency,  as  in  most  cases  variable 
speed  motors  are  of  a  special  nature  and  it  is  much  more  difficult 
to  secure  repair  parts  than  it  is  with  the  constant  speed  motor,  as 
one  can  usually  have  tSe  parts  needed  shipped  directly  from  stock 
and  without  any  delays. 

Another  consideration  should  be  noted.  The  wear  upon  the 
variable  speed  reversing  controller  is  considerable  when  we  take 


410 


MODERN   LATHE  PRACTICE 


into  consideration  the  number  of  times  that  the  lathe  is  stopped, 
started,  and  reversed  each  day 

The  greatest  advantage  is  that  the  induction  motor  is  without 
commutator  troubles,  which  is  the  main  cause  of  difficulties  with  all 
direct-current  motors. 

A  lathe  capable  of  doing  at  one  setting  the  operations  that  would 
require  eight  or  more  settings  of  an  ordinary  engine  lathe  is  the 
24-inch  semi-automatic  turret  lathe,  manufactured  by  the  American 
Turret  Lathe  Company  and  shown  in  Fig.  311  as  a  good  example 
of  this  class  of  machines  so  driven. 


FIG.  311.  —  Heavy  Motor-Driven  Turret  Lathe  built  by  the  American  Turret 

Lathe  Company. 

Being  intended  for  heavier  work  than  is  usually  imposed  upon  a 
turret  lathe,  it  has  a  massive  bed  construction,  a  large  turret,  and  is 
designed  to  swing  27  inches  for  a  distance  of  12  inches  from  the 
chuck. 

Twelve  rates  of  feed  and  feed  reverse  and  eight  speeds  of  the 
spindle  are  possible  with  each  speed  of  the  motor.  The  gear  com- 
binations for  all  these  are  protected  and  may  be  operated  to  effect 
a  change  in  speed  while  the  machine  is  running.  The  levers  for 
the  various  gear  clutches  are  shown  under  the  head.  The  turret 
has  universal  facing  heads  and  provides  for  thirteen  tools,  though 
seldom  more  than  five  are  used  at  a  time. 


ELECTRICALLY  DRIVEN   LATHES  411 

There  is  an  auxiliary  turret  which  will  accommodate  four  tools 
and  has  power  cross  feed  on  one  side  of  the  turret.  The  latter  has 
power  traverse  in  either  direction  by  a  separate  motor,  and  a  slower 
travel  through  the  feeding  mechanism  driven  from  the  spindle. 
Rotating,  indexing,  and  clamping  of  the  turret  hea^d  are  all  auto- 
matic, and  an  independent  " knockout"  or  feed  stop  serves  each 
face. 

The  spindle  is  driven  through  a  Renold  silent  chain  by  a  ten 
horse-power  Crocker- Wheeler  semi-enclosed  motor  mounted  above 
the  head-stock.  An  M.  12  controller  in  the  current  supply  allows 
the  motor  twelve  speeds,  ranging  from  876  to  130  revolutions  per 
minute. 

With  the  combination  of  electrical  and  mechanical  means  the 
highest  and  lowest  possible  chuck  speeds  are  90  and  1  1-5  revolu- 
tions per  minute,  respectively.  For  the  operation  of  the  turret  a 
three  horse-power  Crocker- Wheeler  fully  enclosed  motor  is  used. 
This  runs  continuously  at  a  constant  speed  of  1,000  revolutions  per 
minute  on  a  two-wire  supply,  and  drives  a  steep-pitch  lead  screw 
through  bevel  gearing.  A  longitudinal  shifting  of  the  driven  shaft 
clutches  one  or  the  other  of  the  two  bevel  gears,  producing  direct 
or  reverse  rotation,  or  in  the  central  position  releases  both. 

The  Hendey-Norton  arrangement  of  an  elevated  electric  motor 
operating  a  countershaft  is  shown  in  Fig.  312. 

The  electric-motor  drive,  as  illustrated,  gives  all  the  advantages 
to  be  had  from  regular  countershaft  drive.  It  will  be  noticed  that 
the  motor  is  of  the  back  geared  type.  Carried  on  the  end  of  the 
commutator  shaft  are  two  rawhide  pinions  of  different  diameters, 
driving  two  large  gears  on  the  countershaft  of  the  motor,  the  gear- 
ing being  properly  proportioned  to  give  the  required  driving 
speeds  to  the  countershaft. 

These  large  gears  run  smoothly  on  the  shaft.  Their  inner  for- 
mation is  that  of  the  friction  clutch  pulleys  used  on  their  shapers, 
and  carried  between  them,  keyed  to  but  sliding  on  the  shaft,  is  a 
friction  clutch,  which  is  thrown  into  connection  with  either  gear  as 
desired,  being  operated  by  the  depending  shipper  and  handle  ex- 
tended back  and  supported  in  a  ring  at  the  end  of  the  lathe,  as 
shown. 

The  clutch  is  also  fitted  with  the  usual  locking  spring  and  point. 


412 


MODERN   LATHE   PRACTICE 


We  thus  have  two  speeds  for  the  countershaft,  affording  the  sixteen 
changes  for  the  lathe  spindle.  These  are  accomplished  with  the 
motor  running  at  constant  speed,  thus  maintaining  its  maximum 
efficiency  at  all  times. 

The  reversing  device  for  the  carriage  is  operated  at  the  side  of 
the  apron,  which  allows  the  spindle  to  run  in  the  one  direction,  and 
dispenses  with  the  necessity  of  wiring  the  motor  for  backward  drive, 
an  item  of  expense  and  complication  which  is  avoided. 


FIG.  312.  —  Hendey-Norton  Motor-Driven  Lathe. 

The  standard  carrying  the  motor  is  rigidly  bolted  to  the  lathe 
bed,  and,  being  strongly  webbed,  is  free  from  any  disturbing  vibra- 
tion. The  motor  is  directly  attached  to  a  hinged  plate  on  the  top  of 
the  standard. 

At  the  front  end  of  the  plate  there  is  carried  a  short-throw  cam 
which  allows  the  plate  a  slight  drop  and  consequent  loosening  of  the 
belt  when  it  is  desired  to  shift  from  one  step  of  the  cone  to  another. 
The  cam  rides  upon  adjustable  posts  which  afford  a  means  of  taking 
up  any  slight  stretch  occurring  in  the  belt.  The  motor  back  gear 


ELECTRICALLY  DRIVEN   LATHES 


413 


shaft  is  supported  at  pulley  end  with  an  out-board  bearing,  which 
prevents  any  springing  of  the  shaft  when  the  belt  is  used  on  the 
smaller  steps  of  the  cone. 

The  workmanship  on  the  electric  motors  and  their  connections, 
like  the  work  on  the  lathes  and  other  product  of  this  company,  is 
first-class,  and  the  entire  outfit  is  a  good  example  of  mechanical 
work,  although  it  cannot  be  said  that  the  design  of  the  device,  with 
its  heavy  looking  bracket  supporting  the  countershaft  and  motor,  is 
altogether  pleasing  to  the  eye.  It  has  rather  a  top-heavy  appear- 
ance. 

The  following  illustration,  in  which  Fig.  313  is  a  front  elevation 


FIG.  313.  —  Front  Elevation  —  Electric  Drive  for 
50-inch  Lathe,  designed  by  the  Author. 

and  Fig.  314  an  end  elevation  and  partial  section,  is  of  an  electric 
drive  designed  by  the  author  for  a  50-inch  swing  lathe. 

The  advantages  of  having  a  machine  tool,  particularly  a  large 
one,  driven  by  its  own  individual  electric  motor  are  many,  however 
the  electric  drive  may  be  arranged.  They  are  greater  if  the  ma- 
chine was  originally  designed  to  be  so  driven,  and  particularly  with 
a  variable  speed  motor.  But  it  sometimes  happens  that  we  are 
called  upon  to  arrange  an  electric  drive  to  a  machine  already  built 
and  perhaps  in  use  in  the  shop.  We  may  also  be  required  to  drive 


414 


MODERN   LATHE   PRACTICE 


it  with  a  constant  speed  motor,  and  must  therefore  make  proper 
provisions  for  speed  changes. 

Under  these  conditions  a  large  lathe  had  to  be  arranged  for 
parties  who  insisted  that  the  cone  pulley  in  the  head-stock  should 
be  replaced  by  a  series  of  gears  of  varying  diameters  and  so  arranged 
as  to  engage  any  one  of  a  second  series  of  gears  located  on  a 
supplementary  shaft  in  front  of  them,  the  gears  being  placed  at 
unequal  intervals,  the  smallest  somewhat  greater  than  the  width 
of  their  faces  from  each  other.  The  lathe  was  so  arranged  and 
successfully  used,  yet  the  necessary  complication  of  the  shifting 


FIG.  314.  —  End  Elevation  of  50-inch  Lathe 
with  Electric  Drive  designed  by  the  Author. 


apparatus,  and  the  difficulty  of  readily  bringing  the  proper  gear 
into  engagement  with  its  fellow  by  sliding  the  gear  longitudinally, 
rendered  the  device  somewhat  clumsy  and  inconvenient,  and  was 
the  cause  of  some  bad  language  on  the  part  of  the  man  who  ran  it. 
The  next  occasion  on  which  a  similar  problem  arose  the  customer 
was  not  insistent  upon  any  partiular  plan,  only  he  "  didn't  want  it 
like  the  other  one."  The  motor  to  be  used  was  of  constant  speed 
and  the  following  device  was  adapted  in  attaching  it  to  the  lathe, 
as  shown  by  the  front  elevation  in  Fig.  313,  and  the  end  elevation 
in  Fig.  314. 


ELECTRICALLY  DRIVEN  LATHES  415 

The  countershaft  cone  A  is  mounted  on  a  shaft  journaled  in  the 
brackets  B,  B,  attached  to  the  head-stock,  as  shown.  At  the  rear 
end  of  this  shaft  is  fixed  a  gray-iron  gear  C.  The  motor  D  is  sup- 
ported upon  a  bracket  E  attached  to  the  lathe  bed  and  carries  on 
the  end  of  its  shaft  the  steel  pinion  F.  Between  the  pinion  F  and 
the  gear  C,  and  journaled  on  the  bracket  G  attached  to  the  head- 
stock,  is  a  rawhide  gear  H  engaging  both  of  them.  This  is  intro- 
duced to  avoid  the  noise  which  would  otherwise  be  caused  by  the 
fast-running  pinion  F  on  the  motor  shaft.  The  gear  H  is  con- 
structed with  a  gray-iron  flange  on  each  side,  one  flange  having 
formed  upon  it  a  hub  passing  through  the  rawhide  blank  and  the 
opposite  flange,  and  the  whole  firmly  secured  together  by  six  flush- 
headed  screws,  the  object  of  this  construction  being  to  furnish  a 
good  bearing  on  the  stud  upon  which  it  runs  and  also  to  furnish 
proper  support  for  the  ends  of  the  teeth. 

Upon  the  bosses  of  the  brackets  B,  B,  are  formed  projecting 
sleeves  upon  which  are  journaled  the  arms  J,  J,  in  the  upper  ends 
of  which  is  journaled  the  belt- tightening  roller  K,  which  is  com- 
posed of  a  piece  of  5-inch  extra  thick  wrought  iron  pipe,  provided 
with  gray-iron  heads  through  which  its  shaft  passes.  Through  the 
two  end  portions  of  the  head-stock,  holes  are  drilled  in  which  is 
journaled  the  rock  shaft  L,  upon  which  are  fixed  the  two  levers  M, 
M,  the  upper  ends  of  which  are  connected  to  the  arms  J,  J,  by  the 
connecting  rods  N,  N.  Upon  the  front  end  of  the  rock-shaft  L  is 
fixed  the  worm  segment  P,  which  engages  the  worm  Q,  the  shaft  R 
of  which  is  journaled  in  the  bracket  S  fixed  to  the  front  of  the  head- 
stock,  as  shown  in  Fig.  314.  Upon  the  outer  end  of  the  shaft  R  is 
fixed  the  crank  T  for  operating  the  belt-tightening  device. 

The  belt  V  is  cemented  instead  of  being  laced,  to  facilitate  its 
smooth  running.  By  a  backward  turn  of  the  crank  T  the  belt  V  is 
rendered  slack  enough  to  be  changed  from  one  step  of  the  cone  to 
the  other,  and  a  forward  turn  of  the  crank  tightens  it  as  much  as 
may  be  necessary  to  drive  the  lathe. 

In  practice  it  was  found  that  the  operator  preferred  to  use  the 
crank  for  stopping  and  starting  the  lathe  to  examine  and  caliper 
his  work  rather  than  to  use  the  electric  switch  or  the  rheostat,  claim- 
ing that  it  was  more  convenient  to  allow  the  motor  to  continue  to 
run  and  start  the  lathe  gradually  by  tightening  the  belt  slowly  for 


416  MODERN  LATHE  PRACTICE 

that  purpose,  and  we  must  admit  that  the  operator  of  a  machine, 
in  his  daily  experience,  frequently  finds  convenient  ways  to  "do 
things'.'  that  the  designer  or  the  foreman  may  entirely  overlook. 

While  the  device  here  shown  is  simple,  and  no  claim  is  made 
of  anything  strikingly  new  or  original,  it  has  succeeded  admi- 
rably and  given  good  satisfaction  to  the  proprietors  as  well  as  to 
the  employees  of  the  shop  where  it  is  in  use,  and  will  be  found  an 
economical,  convenient,  and  efficient  method  of  applying  the  elec- 
tric drive  to  existing  lathes. 


CHAPTER  XXIII 

PRACTICAL    INSTRUCTIONS    ON    LATHE    OPERATION 

Setting  up  a  Lathe.  Placing  the  Lathe.  Plan  of  Small  Shop.  Line  Shaft 
Size  and  Speed.  Power  Needed  to  Drive  Lathes.  Leveling  Lathe. 
Lubrication  of  Lathe  Parts.  When  to  Oil.  Attaching  Face  Plate  or 
Chuck.  Lathe  Parts  and  Their  Functions.  Headstock.  Tail  Stock. 
Carriage.  Automatic  Apron.  Reverse  Gear.  Compound  Rest. 
Starting  the  Lathe.  Operating  Levers.  Simple  Lathe  Accessories. 
Spur  and  Screw  Centers.  Drill  Pads.  Turning  a  Steel  Shaft.  Drill- 
ing in  the  Lathe.  Taper  Attachment  for  Lathes.  Milling  in  the  Lathe. 
South  Bend  Attachment.  Barnes  Attachment.  Motor  Driven  At- 
tachment. Knurling  on  the  Lathe.  Indicators  and  Their  Use.  Boring 
Bar  Construction  and  Use.  Adjustable  Boring  Bar.  Boring  Bars  for 
Heavy  Work.  Methods  of  Holding  Work.  Special  Chuck  for  Gas 
Engine  Pistons.  Increasing  Swing  of  Lathe.  Lathes  for  Heavy  Work. 
Grinding  Attachments,  Belt  Driven.  Machining  Concave  and  Convex 
Surfaces.  Grooving  Oil  Ducts.  Combination  Lathe  Dogs  and  Their 
Use.  Hacksaw  Attachment  for  Lathes. 

IP  the  Lathe  is  purchased  new,  it  will  undoubtedly  come  crated 
up  in  a  substantial  manner  with  all  auxiliary  parts  wrapped  in  bur- 
lap with  excelsior  padding.  A  list  of  parts  included  in  the  pur- 
chase price  should  be  carefully  checked  against  the  shipment  to 
insure  that  all  are  received.  The  wrappings  should  be  carefully 
removed  and  inspected  to  see  that  no  small  parts  are  overlooked. 
It  will  be  noticed  that  all  bright  parts  are  covered  with  vaseline. 
This  precaution  is  taken  to  reduce  liability  of  rusting  during  ship- 
ment. This  may  be  easily  removed  with  a  cloth  dipped  in  kero- 
sene, after  which  the  parts  are  wiped  dry.  The  gears  should  be 
cleaned  thoroughly  and  all  chips,  excelsior  shreds  or  sawdust 
removed  from  each  tooth  separately.  This  includes  change  speed 
gears  as  well  as  back  gears. 

417 


418 


MODERN  LATHE  PRACTICE 


The  placing  of  the  lathe  in  the  shop  depends  upon  many  con- 
ditions such  as  position  of  drive  shafting,  opportunity  for  counter- 
shaft installation,  relation  to  work  bench,  direction  of  light,  etc. 
It  is  claimed  by  experienced  mechanics  that  the  operator  can  work 
most  efficiently  with  the  light  coming  from  a  point  over  the  right 
shoulder.  The  floor  supporting  the  lathe  should  be  firm  and 
level.  If  there  is  any  vibration  after  the  lathe  is  started,  the 
floor  should  be  suitably  braced  from  underneath,  if  possible.  The 


GRINDER  COUNTERSHAFT^ 

GRINDER 


FIG.  315.  —  Plan  View  of  Small  Shop  Showing  Arrangement  of  Shafting  and 

Location  of  Lathe. 

lathe  should  be  placed  so  the  operator  can  readily  gain  access  to 
all  sides  as  there  are  many  jobs  that  require  the  operator  to  work 
at  all  sides  of  the  machine. 

The  general  arrangement  of  the  lathe,  its  countershaft  and 
line  shaft  to  drive  it  as  well  as  two  sources  of  power  that  can  be 
used  as  recommended  by  the  South  Bend  Lathe  Works  are  clearly 
shown  in  Figs.  315  and  316.  The  plan  view  shows  the  location  of 
the  machine  relative  to  the  bench,  as  well  as  the  placing  of  the 
line  shaft  so  it  can  be  driven  by  either  an  electric  motor  or  small 
gas  engine,  and  drive  not  only  the  lathe  countershaft  but  an  emery 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     419 

wheel  stand  as  well.  The  view  at  Fig.  317  is  a  front  view  of  the 
lathe  and  countershaft  and  is  lettered  so  the  principal  dimensions 
of  a  lathe  may  be  clearly  grasped  by  the  novice  machinist.  The 
swing  A  is  twice  the  radius  R,  and  indicates  the  diameter  of  the 
largest  piece  that  can  be  turned  supported  by  the  centers.  The 
distance  between  centers  B  indicates  the  maximum  length  that 
can  be  turned  between  these  points  of  support.  The  length  of  the 
bed  is  indicated  bv  C. 


FIG.  316.  —  View  of  Small  Machine  Shop  Showing  Relation  of  Lathe  to 

Workbench. 

It  is  said  that  the  countershaft  should  be  placed  at  least  five 
feet  above  the  spindle  in  order  to  secure  proper  belt  tension  and 
that  six  or  seven  feet  would  be  even  better.  The  countershaft 
may  be  set  either  side  of  the  line  shaft  depending  upon  position  of 
the  lathe.  The  shipper  rod  actuating  lever  must  be  conveniently 
placed  so  it  may  be  readily  operated  by  the  lathe  user.  When 
the  lathe  location  is  settled,  the  countershaft  should  be  perma- 
nently installed.  For  a  light  lathe,  the  countershaft  hangers  can 
be  secured  to  cross  pieces,  about  2"  x  4",  which  are  attached  to  the 
ceiling  beams  parallel  with  the  lathe  ways  and  sufficiently  far  apart 


420 


MODERN  LATHE  PRACTICE 


to  make  possible  the  retention  of  the  hanger  feet  by  lag  screws. 
The  countershaft  support  pieces  should  be  secured  to  the  ceiling 
by  substantial  fastenings,  lag  screws  being  the  most  common. 

The  usual  method  of  supporting  the  line  shaft  is  by  the  joists 
which  run  from  the  side  walls.  If  the  shop  is  a  small  one,  including 
only  a  lathe,  emery  grinder  and  perhaps  a  drill  press,  a  1TV 


Countershaft 


Tail  Stock 


FIG.  317.  —  View  of  Lathe  Showing  Important  Dimensions. 

will  be  ample.  The  line  shaft  hangers  should  be  placed  eight  feet 
apart  and  a  shaft  speed  of  200  to  300  R.  P.  M.  is  considered  suffi- 
ciently fast,  the  average  speed  being  250  R.  P.  M.  If  electric  power 
is  available,  a  small  motor  may  be  secured  to  a  suitable  bracket 
attached  to  the  side  wall,  care  being  taken  to  place  the  motor  high 
enough  so  the  belt  leading  from  it  to  the  line  shaft  will  not  inter- 
fere with  anyone  having  occasion  to  pass  under  it.  If  a  gas  or 
gasoline  engine  is  used  instead  of  an  electric  motor  the  engine  may 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION    421 

be  placed  in  any  convenient  location,  though  usually  it  is  put  in  a 
corner  where  it  will  be  out  of  the  way. 

If  the  lathe  is  not  larger  than  16"  swing,  a  gas  engine  of  2|  to 
3  H.  P.  will  be  ample,  while  an  electric  motor  of  1 J  to  2  H.  P.  will 
provide  sufficient  power.  The  horse  power  needed  to  drive  a  lathe 
varies  with  the  size  and  character  of  the  work.  Obviously,  the 
motor  power  should  be  ample  so  the  lathe  can  work  at  full  capacity. 
A  12"  swing  lathe  will  take  |  H.  P.  under  these  conditions,  a 
13"  will  take  }  H.  P.  About  1  H.  P.  should  be  allowed  for  a 
15"  swing,  2  H.  P.  for  a  16"  swing  lathe  while  not  less  than 
1\  H.  P.  should  be  supplied  to  turn  an  18"  swing  machine  at  maxi- 
mum load.  The  shafting  friction  in  a  small  shop  of  the  character 
indicated  at  Fig.  315,  providing  the  line  shaft  is  properly  aligned 
and  well  oiled,  would  not  be  any  more  than  \  H.  P.  This 
figure  must  be  added  to  the  energy  necessary  to  turn  the  lathe. 

When  the  countershaft  is  properly  fastened  in  position,  move 
the  lathe  over  until  the  driving  belt  will  track  properly  between 
spindle  cone  pulley  and  countershaft  pulley  group.  The  axis  of 
the  lathe  spindle  should  be  parallel  with  that  of  the  countershaft. 
Upon  the  proper  leveling  of  the  lathe  much  depends,  as  the  way 
the  lathe  is  erected  has  much  to  do  with  its  accuracy.  A  car- 
penter's level  should  be  placed  across  the  ways  near  the  head 
stock.  Repeat  this  operation  at  various  points  along  the  length 
of  the  bed,  leveling  carefully  in  every  direction.  If  the  lathe  bed 
is  not  plumb,  put  a  shim  between  the  low  leg  and  the  floor.  Shingles 
are  a  favorite  shim  among  millwrights  on  account  of  the  taper 
which  makes  it  possible  to  level  very  accurately  by  driving  two 
shingles  in  opposite  directions  under  the  lathe  leg  to  raise  it  grad- 
ually. When  properly  leveled,  as  can  be  easily  determined  by  using 
the  level  both  parallel  to  the  ways  and  across  them  as  well,  the 
pads  or  feet  at  the  bottom  of  the  legs  are  securely  lagged  to  the 
floor.  If  the  floor  is  of  cement  or  concrete,  it  is  necessary  to  drill 
out  holes  and  drive  in  wooden  plugs  in  order  to  secure  anchorage 
for  the  lags.  Expanding  bolts  are  also  sometimes  used  for  this 
purpose. 

In  belting  up  the  lathe,  most  mechanics  favor  leather  belts. 
The  belt  nearest  the  lathe  head  is  usually  straight,  while  the  other 
is  generally  a  crossed  belt  to  give  reverse  motion.  The  counter- 


422  MODERN  LATHE  PRACTICE 

shaft  belts  should  be  so  arranged  that  when  the  shipper  rod  is  moved 
in  the  direction  of  the  lathe  head,  the  spindle  of  the  lathe  should 
revolve  so  the  top  of  the  spindle  cone  pulley  group  turns  toward 
the  operator  when  he  is  standing  in  front  of  the  lathe. 


LUBRICATION  OF  LATHE  PARTS 

To  secure  proper  results  from  a  lathe  or  other  machine  tool  it 
is  necessary  to  keep  all  working  parts  properly  lubricated  as  the 
neglect  of  this  essential  precaution  means  rapid  depreciation  of 
the  various  members  upon  which  the  maintenance  of  accuracy 
depends.  Lubricating  oil  should  be  of  the  best  quality  and  free 
from  acid.  After  lathe  is  properly  located,  the  various  revolving 
parts  of  the  lathe  and  the  countershaft  bearings  are  well  lubri- 
cated. The  various  oil  holes  are  usually  clearly  indicated  by  small, 
plugs  having  a  knob  on  the  end  by  which  they  may  be  removed 
easily.  After  flushing  the  bearings  liberally  with  oil,  the  plugs 
are  reinserted  in  the  oil  holes  to  keep  dust  and  dirt  out.  The 
main  spindle  bearings  are  usually  provided  with  oilers  of  this  type. 
The  spindle  drive  cone  bearings  are  oiled  by  removing  small  headless 
set  screws  located  on  both  large  and  small  steps  of  the  pulley 
group.  The  back  gear  quill  bearings  are  oiled  through  small  oil 
holes  on  that  member.  Use  plenty  of  oil  on  the  lead  screw  and 
half  nuts  before  cutting  a  thread  to  prevent  cutting  the  babbit 
metal  in  the  half  nuts.  Oil  the  head  spindle  bearings  at  least  every 
day  and  if  the  lathe  is  on  hard  work,  it  will  be  well  to  supply  oil 
copiously  several  times  every  day.  The  mechanism  of  the  apron, 
the  lead  screw  bearings,  the  change  speed  or  feed  gears  and  all 
other  parts  should  be  well  oiled  at  all  times. 

After  the  lathe  is  well  oiled,  run  it  for  a  few  minutes  after  it  is 
first  installed  to  make  sure  that  there  is  no  binding  in  the  bearings, 
or  that  they  are  not  adjusted  too  tightly.  Heating  indicates 
friction  due  to  lack  of  oiling,  poor  bearing  alignment  or  too  tight 
adjustment.  Wipe  all  surplus  oil  from  the  outside  of  the  parts  as 
it  serves  no  useful  purpose  and  may  actually  be  detrimental  be- 
cause it  will  collect  chips,  dirt,  etc.  Wipe  the  ways  over  with  an 
oily  rag  to  make  sure  that  tail  stock  and  carriage  move  back  and 
forth  freely.  Before  attaching  a  face  plate  or  chuck  on  the  nose 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     423 

of  the  spindle  all  dirt  should  be  removed  from  the  threads  on  spindle 
as  well  as  from  female  threads  inside  the  chuck  or  in  the  face  plate 
boss.  The  back  of  face  plate  or  chuck  should  fit  tightly  against 
the  shoulder  at  the  end  of  the  thread  spindle  nose.  Before  fitting 
the  centers,  drill  pads  or  taper  shank  drills  in  the  spindle  and 
tail  stock  clean  out  the  tapered  holes  thoroughly  to  remove  all 
chips.  A  small  chip  will  prevent  the  center  from  fitting  properly 
and  inaccurate  work  will  result  because  centers  are  not  in  line. 

LATHE  PARTS  AND  THEIR  FUNCTIONS 

The  main  parts  of  a  typical  screw  cutting  lathe  are  clearly 
shown  in  Fig.  318.  The  view  at  A  is  from  the  end  showing  screw 
cutting  and  feed  gears,  that  at  B  is  a  front  view  showing  the  parts 
convenient  to  the  operator.  While  the  various  important  lathe 
parts  have  been  outlined  in  other  portions  of  the  book  it  may  be 
well  to  review  these  so  the  novice  operator  can  understand  the 
parts  and  what  they  are  for.  The  main  portion  of  any  lathe  is 
the  bed  which  is  supported  at  the  right  height  from  the  floor  by 
cast  iron  legs.  The  bed  supports  the  head  stock  at  one  end,  this 
in  turn  carries  the  spindle  to  which  face  plate  or  chuck  is  fastened. 
The  spindle  is  supported  by  bearings  and  is  driven  by  either  of  two 
methods.  With  the  back  gears  out,  the  cone  pulley  group  may 
be  locked  to  the  spindle  by  a  simple  clutch  pin,  which  gives  the 
highest  spindle  speed.  With  the  clutch  pin  out,  the  pulley  group 
will  turn  without  turning  the  spindle.  With  the  back  gear  in  and 
the  clutch  pin  out,  the  spindle  will  be  turned  at  a  low  speed  de- 
termined by  the  back  gear  reduction.  Some  work  can  be  done 
better  with  the  spindle  turning  fast,  such  as  wood  and  brass  turning, 
filing,  finishing,  etc.,  while  "hogging"  or  removing  much  metal 
by  taking  heavy  chips  always  requires  the  use  of  the  back  gears. 
The  carriage  consists  of  two  parts,  a  portion  resting  on  the  ways 
of  the  lathe  bed  carrying  the  cutting  tool  and  an  apron  attached 
to  it  that  carries  the  mechanism  used  in  moving  the  carriage  back 
and  forth  under  the  action  of  the  lead  screw.  The  lead  screw 
determines  the  lateral  feed  or  movement  of  the  carriage  from  end 
to  end  of  the  lathe. 

The  tail  stock  of  all  lathes  is  adjustable  along  the  ways  and 
supports  one  center.  The  center  is  mounted  in  a  movable  barrel 


424 


MODERN  LATHE  PRACTICE 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION      425 

in  the  tail  stock.  This  barrel  may  be  moved  back  and  forth  by 
a  screw  turned  by  hand  wheel  A  and  locked  absolutely  in  place 
at  any  position  by  lever  C.  The  tail  stock  may  be  locked  by  a 
suitable  lever  which  clamps  it  to  the  bed.  The  lead  screw  may  be 
driven  at  various  speeds  by  varying  the  gear  ratios  and  may 
be  turned  in  either  direction  by  moving  lever  E.  The  tool  post  is 
usually  carried  by  a  compound  rest  attached  to  the  carriage.  A 
compound  rest  makes  it  possible  to  feed  the  tool  in  or  out  in  a 
direction  parallel  to  the  ways  by  lever  A  and  in  a  direction  at  right 
angles  to  the  ways  by  lever  B  and  also  to  set  the  tool  at  any  desired 
angle  with  the  work.  Both  levers  may  be  worked  simultaneously. 
The  reverse  gear  is  brought  in  action  by  lever  E  on  the  end  of  the 
head  stock.  The  carriage  may  be  moved  manually  when  desired 
by  hand  wheel  B.  The  small  knob  on  wheel  C  actuates  a  clutch 
for  the  carriage  cross  feed,  while  lever  D  makes  the  connection 
between  the  half  nuts  carried  by  the  carriage  and  the  lead  screw 
in  thread  cutting. 

The  parts  of  the  countershaft  assembly  overhead  are  easily 
identified.  The  countershaft  carries  a  pulley  cone  group  to  drive 
that  on  lathe  head  stock.  The  small  step  of  the  countershaft 
cone  is  belted  to  the  large  step  of  the  spindle  drive  cone.  Two 
friction  clutches  are  used,  one  being  driven  by  a  crossed  belt  to 
obtain  reverse  motion.  The  shipper  handle  actuates  the  clutch 
cone  and  is  in  turn  operated  by  a  shipper  bar  making  it  easy  to 
operate  the  clutches  from  any  part  of  the  lathe. 

An  interior  view  of  the  usual  form  of  automatic  apron  furnished 
on  South  Bend  lathes  is  shown  at  Fig.  319-A.  It  will  be  noted 
that  the  lead  screw  is  provided  with  a  spline  which  drives  the 
worm  operating  the  power  cross  feed  and  the  automatic  longitu- 
dinal feed.  The  half  nuts,  which  are  used  in  screw  cutting,  are 
clearly  shown.  The  various  levers  and  wheels  previously  described 
are  also  indicated.  The  reverse  of  the  South  Bend  Lathe  is  shown 
at  Fig.  319-B.  The  reverse  gear  carrier  may  be  rocked  so  either 
gear  A  or  B  is  in  mesh  with  spindle  gear  C  or  it  may  be  left  in  a 
neutral  position  with  both  gears  out  of  mesh  when  it  is  desired 
to  run  spindle  on  the  direct  drive  for  polishing,  etc.  The  graduated 
compound  rest  is  shown  at  319- C.  In  addition  to  enabling  both 
cross  and  longitudinal  tool  post  feed,  the  rest  swivels  in  a  complete 


426 


MODERN  LATHE  PRACTICE 


Half  Nubs 


Wheel 
B 


Reverse  Gear 
Carrier 


B 


Compound  Idler 
Gear 


Lead  Screw 
Drive 
Gear 


for  Tool  Post 

Chip  Guard 


^Compound  Rest  Swivel  Bolt 
Compound  Rest  Top 


FIG.  319.  — Views  of  Important  Lathe  Part  Assemblies  Making  Design  and 
Location  of  Components  Clear. 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     427 

circle  and  is  clamped  in  any  position  desired  by  T  head  bolts. 
The  graduation  is  such  that  it  may  be  set  for  any  angle. 

STARTING  THE  LATHE 

Before  starting  to  do  any  work  on  the  lathe,  it  is  important  to 
become  familiar  with  the  method  of  working  the  various  control 
levers  and  wheels  and  of  locking  the  adjustments  to  prevent  move- 
ment when  they  are  set  properly.  Th,e  first  thing  to  do  is  to  try 
and  run  the  spindle  drive  pulley  cone  free.  This  is  done  by  making 
sure  back  gears  are  not  in  mesh  and  releasing  bull  gear  clamp  or 
locking  pin  that  joins  the  large  gear  just  back  of  the  front  spindle 
bearing  to  the  pulley  group.  If  the  lathe  runs  freely  in  this  posi- 
tion, which  is  called  "in  open  belt"  by  some  machinists,  throw  in 
the  back  gears  and  notice  that  spindle  turns  slower  than  the  pulley 
group.  This  is  done  by  rocking  the  lever  F,  Fig.  318-A,  so  the 
gears  on  back  gear  quill  mesh  with  those  on  the  spindle.  The 
gears  should  not  mesh  deep  enough  to  bottom.  To  run  lathe  on 
direct  drive  throw  out  back  gears  and  lock  the  bull  gear  clamp. 
The  pulley  group  and  lathe  spindle  speeds  are  now  the  same. 
Lathe  manufacturers  caution  the  operator  not  to  throw  back 
gears  in  or  out  when  lathe  is  running.  To  connect  the  reverse 
gear,  rock  the  lever  E,  Fig.  319-B,  till  either  gear  A  or  B  is  in 
mesh  with  C,  depending  upon  the  direction  of  lead  screw  rotation 
desired.  The  same  caution  given  about  putting  back  gears  in  mesh 
with  lathe  running  applies  just  as  well  in  this  case. 

SIMPLE  LATHE  ACCESSORIES 

The  lathe  may  be  used  to  do  almost  any  work  that  other  ma- 
chine tools  can  do  if  supplied  with  the  proper  attachments.  Drill- 
ing, grinding,  milling  and  boring  may  be  accurately  performed  by 
using  various  attachments  to  be  described  in  proper  sequence. 
We  will  first  discuss  the  methods  of  doing  simple  jobs  and  then 
will  show  some  methods  pertaining  to  harder  work.  A  number  of 
lathe  accessories  that  are  inexpensive,  yet  very  useful,  are  shown 
at  Fig.  320.  The  spur  center  at  A  is  used  in  wood  turning,  espe- 
cially for  long  work.  It  is  intended  for  use  in  the  lathe  spindle 
and  not  only  supports  the  work  but  drives  it  as  well  when  the  spurs 


428 


MODERN  LATHE  PRACTICE 


or  lips  are  forced  into  the  end  of  the  piece  to  be  turned.  The 
screw  center  B  is  for  turning  large  wood  pieces  that  cannot  be  very 
well  supported  by  both  head  and  tail  stock  centers.  The  cup 
center  C  is  used  in  connection  with  either  of  the  others  in  wood 
turning  and  is  generally  used  in  the  tail  stock.  When  drilling 
with  square  shank  drills  and  bits  the  special  drill  chuck  at  D  will 
be  found  useful.  The  form  shown  is  provided  with  a  female  thread 
to  fit  the  lathe  spindle  nose.  The  drill  or  bit  is  clamped  in  place 


Spur  Center 


Cup  Center 


Screw   Center 


Special  Drilling  Chuck 


Crotch  Center 


Drill  Pad 


FIG.  320.  —  Some  Useful  Lathe  Accessories. 

by  a  set  screw.  The  drilling  pad  with  V  groove  shown  at  E,  some- 
times called  a  crotch  center,  is  very  useful  when  drilling  round  bars 
as  it  supports  these  and  centers  them  automatically.  The  drill 
pad  shown  at  F  is  used  in  the  tail  stock  (as  is  the  crotch  center  E) 
as  a  support  for  any  piece  drilled,  and  is  designed  for  use  with 
flat  stock. 

TURNING  A  STEEL  SHAFT 

The  simplest  thing  to  do  on  a  lathe  and  one  that  will  give  the 
apprentice  opportunity  to  become  thoroughly  familiar  with  all 
levers,  etc.,  is  turning  a  steel  shaft.  The  various  forms  of  lathe 
tools  available  and  their  method  of  use  are  fully  described  in 
Chapter  XI,  while  the  forms  of  lathe  dogs  and  proper  use  of  centers 
are  fully  outlined  in  Chapter  XIII.  The  first  thing  to  do  is  to 
provide  centers  in  the  shaft  with  a  combined  drill  and  center 
countersink  in  order  to  support  it  properly  on  the  lathe  centers. 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     429 


The  steps  are  first,  to  mark  the  end  of  the  shaft  which  is  done  by 
scratching  two  lines  at  right  angles.  The  point  of  intersection  of 
the  lines  is  where  the  center  should  be.  To  mark  the  place,  a 
center  punch  is  used  as  shown  at  Fig.  321-A.  Place  the  shaft 
between  the  lathe  centers  after  prick  punching  both  ends  and 
see  if  it  runs  true  when  revolved  by  hand.  If  it  runs  out  hold  a 
piece  of  chalk  to  the  shaft  while  it  turns  and  mark  the  high  spots. 
Drive  the  center  hole  over  in  the  direction  necessary  to  have  the 
shaft  run  true  with  center  punch;  in  most  cases  it  will  mean  moving 


WORK 


CHUCK 


SIDE  TOOL 


.WORK  TA1L5TOCK  CENTER 

'  rty 


FIG.  321.  —  Preliminary  Steps  to  Turning  and  Facing  Steel  Shaft  on  the 

Lathe. 

the  center  nearer  the  high  spot.  The  method  of  countersinking 
a  shaft  is  shown  at  Fig.  321-B.  A  drill  chuck  is  placed  in  the 
lathe  spindle  and  fitted  with  a  combined  drill  and  countersink. 
Place  one  end  of  the  shaft  on  the  tail  center  and  feed  the  bar  in 
by  turning  the  hand  wheel  at  the  end  of  the  tail  stock.  Allow  the 
countersink  to  feed  in  deep  enough,  then  reverse  the  shaft  and 
countersink  the  other  end  in  the  same  manner.  The  countersink 
should  be  drilled  deep  enough  so  the  point  of  the  center  will  not 
be  called  upon  to  do  any  of  the  work  of  supporting  the  shaft.  The 


430  MODERN  LATHE  PRACTICE 

countersink  should  have  the  same  taper  as  the  lathe  center  or  60 
degrees,  as  fully  outlined  in  a  previous  chapter. 

The  shaft  is  then  provided  with  a  dog  at  one  end  that  engages 
with  a  slot  in  the  face  plate  to  drive  the  piece  and  is  supported  by 
the  tail  stock  center  at  the  other  end.  Oil  the  centers  well  before 
starting  to  turn  the  lathe.  The  shaft  should  have  a  slight  play 
between  the  centers  in  order  that  it  turn  easily.  Select  the  proper 
tool  (Chapter  XI)  for  the  character  of  the  work  and  place  it  in 
the  tool  post,  having  the  cutting  point  or  edge  as  near  the  tool 
post  as  possible  to  prevent  the  tool  springing  under  a  heavy  cut. 

The  position  of  a  turning  tool  is  very  important  when  machining 
metal.  At  Fig.  321- C  the  usual  position  is  shown.  This  is  about 
5  degrees  measured  on  the  circumference  of  the  piece  to  be  turned 
above  the  center  line.  If  a  tool  is  placed  below  center,  it  is  apt 
to  dig  in. 

The  proper  speed  and  feed  to  use  is  only  determined  by  experi- 
ence. It  is  best  for  the  beginner  to  take  light  chips  at  the  start. 
After  the  tool  has  been  properly  set,  move  the  carriage  over  to  the 
tail  stock  end  of  the  bar  and  feed  in  the  hand  cross  feed  until 
the  tool  is  slightly  below  the  surface  of  the  bar  at  one  end.  Set 
the  lead  screw  gears  for  medium  speed  and  feed  the  tool  into  the 
bar  slowly  by  hand  to  make  sure  that  the  chip  taken  will  not  be 
too  heavy  for  the  lathe.  After  the  chip  is  started,  the  automatic 
longitudinal  feed  may  be  locked  in  and  the  tool  moved  by  power. 

Before  taking  the  final  or  finishing  chips  and  polishing  the  shaft 
it  will  be  well  to  face  off  the  shaft  end.  This  is  done  with  a  side 
tool  as  shown  at  Fig.  321-D.  If  the  end  of  the  shaft  is  very  rough 
it  may  be  better  to  face  it  off  before  starting  to  turn  it  down  in 
order  to  secure  an  accurate  cut.  On  reaching  the  countersink 
hole,  the  side  tool  may  be  fed  in  further  to  face  the  end  of  the 
shaft  clean  by  slightly  withdrawing  the  tail  stock  center. 

DRILLING  IN  THE  LATHE 

A  lathe  may  be  used  as  a  horizontal  drilling  machine  and  both 
sensitive  and  large  drill  presses  are  really  developments  of  the 
lathe.  The  drill  press  is  a  vertical  lathe  without  any  provision 
for  mounting  turning  tools.  The  use  of  a  horizontal  table  on  a 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     431 


drill  press  makes  it  more  suitable  for  handling  large  and  heavy 
work  as  the  weight  of  the  pieces  drilled  serve  to  hold  them  in  place 
on  the  table.  A  lathe  can  be  used  in  drilling,  only  it  is  more  diffi- 
cult to  support  the  work  when  it  is  bulky  or  heavy.  The  simplest 
method  of  drilling  is  to  place  the  drill  in  the  lathe  chuck  and  hold 
the  piece  to  be  drilled  by  hand  against  the  drill  pad  held  in  the  tail 
stock,  using  the  tail  stock  hand  wheel  to  feed  the  work  against 
the  drill.  In  this  case,  the  drill  turns  as  it  does  in  a  drilling  machine 
and  the  work  remains  stationary.  The  lathe  chuck  or  face  plate 
is  often  employed  to  hold  the  work  to  be  drilled  as  at  Fig.  322-A 


Lathe  ChucK. 


Drill  Chuck 


Drill 


FIG.  322.  —  Methods  of  Drilling  in  the  Lathe. 

while  the  drill  chuck  is  supported  by  the  tail  stock.  The  method 
of  supporting  a  piece  when  a  long  hole  is  to  be  drilled  by  using  a 
center  rest  or  back  rest  clamped  to  the  ways  of  the  lathe  is  clearly 
shown  at  Fig.  322-B.  The  use  of  a  centering  tool  which  is  held 
in  the  tool  post  is  outlined  in  this  view.  The  drill  is  held 
by  the  tail  stock  in  the  same  manner  as  at  A  except  that  in  many 
cases,  when  the  drill  is  very  long,  the  tool  post  may  be  used  to 
support  the  drill  after  it  has  entered  the  bar  far  enough  to  center 
itself. 


432 


MODERN  LATHE  PRACTICE 


TAPER  ATTACHMENT  FOR  LATHES 

The  common  method  of  turning  a  taper  on  a  piece  in  a  lathe 
is  described  in  Chapter  XIV  and  is  very  easily  done.  The  tail 
stock  is  set  off  center  a  sufficient  distance  to  give  the  required 
taper,  which  may  be  done  on  the  South  Bend  lathes  as  indicated 
at  Fig.  323-A.  The  tail  stock  clamp  is  loosened  and  set  screw  F 
is  unscrewed  the  proper  distance,  then  set  screw  G  is  turned  in 
until  the  tail  stock  is  stopped  by  set  screw  F.  The  tail  stock  is 


Headstock      Dqd  t  Saddle 

\  /  *  Work        \ 


Com 
Res 
Lathe  Bed 

RetainincL^ 


SCREW 


Guide  Block 


FIG.  323.  —  How  to  Turn  Tapers  in  a  Lathe.     A  —  By  Offset  Tail  Stock. 
B  —  With  Taper  Attachment. 

then  clamped  to  the  bed  and  a  chip  is  taken.  Test  the  piece  to 
make  sure  that  the  taper  is  correct  by  trying  in  tapered  hole  it  is 
to  fit. 

Where  a  large  number  of  taper  pieces  are  to  be  turned  in  dupli- 
cate, as  in  manufacturing,  a  taper  attachment  as  shown  at  Fig. 
323-B  may  be  employed.  This  is  fitted  to  the  rear  V  of  the  lathe 
bed  by  two  clamps  and  the  position  of  the  guide  bar  regulating 
the  taper  is  easily  altered  by  changing  the  angle  of  the  guide.  A 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION      433 

block  runs  along  the  guide  bar  and  moves  the  tool  post  carriage 
in  or  out  by  a  connecting  bar.  The  desired  angle  of  the  guide 
bar  is  set  by  loosening  the  retaining  screws  at  each  end  and  setting 
it  at  the  inclination  desired,  after  which  the  screws  are  again 
tightened  down. 

MILLING  IN  THE  LATHE 

A  number  of  milling  attachments  for  use  with  the  lathe  have 
been  offered,  some  of  which  are  very  practical,  others  that  are  not 
so  good.  A  carefully  designed  and  well  constructed  attachment 
of  this  nature  is  clearly  shown  at  Fig.  324  doing  various  grades  of 
milling  work.  This  is  built  by  the  South  Bend  Lathe  Works  and 
while  made  for  lathes  of  their  manufacture  it  is  equally  valuable 
on  other  lathes  of  similar  design.  The  attachment  is  fitted  to  the 
top  of  the  carriage  taking  the  place  of  the  upper  portion  of  the 
compound  rest.  It  is  located  by  a  dowel  pin  or  centering  pin 
projecting  from  the  base.  The  fixture  is  fastened  to  the  compound 
rest  with  two  bolts,  in  just  the  same  way  as  the  compound  rest 
upper  portion  is  fastened.  The  milling  attachment  is  specially 
valuable  for  the  small  shop  as  it  permits  one  to  use  the  lathe  for 
various  jobs  that  ordinarily  could  be  done  only  with  a  shaper  or 
milling  machine.  As  an  attachment  of  this  kind  swivels  all  the 
way  around  on  a  horizontal  plane  and  is  graduated  in  degrees,  as 
well  as  permitting  it  to  be  swiveled  in  a  vertical  plane,  many  forms 
of  work  can  be  economically  performed.  The  vertical  adjusting 
screw  has  a  graduated  collar  reading  in  one  thousandths  of  an' 
inch  thus  making  the  attachment  suitable  for  fine  work  as  well  as 
a  large  variety  of  work. 

The  illustration  at  Fig.  324-A  shows  the  use  of  an  angle  milling 
cutter  in  forming  a  piece  of  cast  iron  held  in  the  vise  of  the  milling 
fixture.  The  length  of  the  cut  is  controlled  by  the  cross  feed 
screw,  the  depth  by  the  adjustment  of  the  lathe  carriage  and  the 
vertical  adjustment  governed  by  the  vertical  screw  of  the  attach- 
ment. At  B,  the  attachment  is  shown  holding  a  steel  shaft  that 
is  being  keyseated  for  a  Woodruff  key.  The  view  at  C  shows 
the  method  of  milling  a  square  on  a  shaft.  The  same  method  can 
be  used  to  cut  off  shafting  or  tubing  by  substituting  a  saw  for  a 
milling  cutter.  The  usual  form  of  milling  cutter  shown  at  D 


434 


MODERN  LATHE  PRACTICE 


is  used  in  connection  with  the  special  arbor  at  E  which  is  made 
to  fit  the  taper  hole  in  the  head  spindle  of  the  lathe.  Any  milling 
cutter  may  be  used,  the  form  depending  upon  the  character  of  the 
piece  to  be  machined. 

The  Barnes  Milling  Attachment  shown  at  Fig.  325  can    be 
conveniently  secured  to  any  lathe  and  is  adapted  to  all  classes  of 


Vertical  Teed  Control 
Clamp^  Screws^ 

ft 

Work 
Cross  Feed 


Woodruff  Key 
Cutter 


Work 

Clamp 

Screws! 


(Lvertical  Feed 
****     Control 
JUT  /Milling  Cutter 

SpinJleNDse 

c 


Arbor 


5haf 


Headstock 


Blocks 


Collar  on  Arbor  ciampNut 


FIG.  324.  —The  South  Bend  Milling  Attachment  and  Its  Use. 

the  most  accurate  milling  and  gear  cutting.  It  is  practically  a 
universal  attachment  and  can  do  any  work  that  can  be  done  on  a 
milling  machine  of  equivalent  capacity.  It  will  make  milling 
cutters,  can  be  used  for  fluting  taps  and  reamers,  for  cutting  spur 
and  bevel  gears,  for  surface  milling,  slotting,  etc.  The  cutter  block 
is  attached  to  the  cross  slide  of  the  lathe  carriage,  can  be  moved 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     435 

in  or  out  and  the  cutter  can  be  adjusted  up  and  down  on  the  arbor 
to  accommodate  work.  The  universal  head  is  clamped  to  the 
inside  ways  of  the  lathe  bed  and  has  longitudinal,  cross  and  vertical 
slides.  The  feed  screws  are  graduated  to  read  in  thousandths  of 
an  inch  and  the  vertical  and  horizontal  swivels  are  graduated  180 
degrees,  this  permitting  very  accurate  adjustments  and  cuts  to  be 
made  at  any  angle.  Either  power  feed  or  hand  crank  on  apron 


Spur  Gear  Blank       ^    jndex 

Driven     I      ^wr- 
Driving  Gear    Gear      j  *^\    Milling 

HeadstockX  ^Attachment 


Cutter 

•Cross  Feed  Lever 
Cutter  Drive  Sears 


FIG.  325.  —  The  Barnes  Milling  Attachment. 

may  be  used  to  feed  cutter  to  work  and  longitudinal  feed  of  universal 
head  may  be  used  to  increase  length  of  feed.  The  spindle  of  the 
universal  head  can  be  supplied  fitted  with  a  draw  in  chuck  attach- 
ment. The  device  will  cut  gears  as  large  as  the  lathe  will  swing. 
A  complete  index  is  furnished  and  it  is  said  that  all  numbers  of 
teeth  can  be  cut  from  1  to  50  and  nearly  all  up  to  360.  Standard 
milling  cutters  are  used.  The  following  specifications  give  some 
idea  of  the  size  of  the  attachment. 


436  MODERN  LATHE  PRACTICE 

Longitudinal  Feed 4f" 

Cross  Feed 10£" 

Vertical  Feed 4f" 

Travel  of  Cutter 3£" 

Distance  between  Centers  of  Spindle  and  Over- 
hanging Arm  .  . 9" 

Swing  on  Centers  between  Overhanging  Arm 4^" 

Distance  between  Vise  Jaws 2f " 

Size  of  Vise  Jaws 4|"  X  1 

Diameter  of  Arbor f " 

The  views  at  Fig.  326  show  the  practical  application  of  the  de- 
vice to  a  variety  of  work.  Fig.  325  shows  the  general  construction 
very  clearly.  The  cutter  is  driven  by  spur  and  spiral  gears.  A 
driving  gear  is  attached  to  the  lathe  spindle,  this  serving  to  transmit 
motion  through  an  idler  gear  to  a  small  gear  mounted  .at  one  end 
of  the  enclosed  cutter  drive  shaft.  The  shaft  carries  a  spiral  gear 
at  the  cutter  end  of  the  housing  and  drives  the  cutter  spindle 
through  the  spiral  gear  at  its  lower  end.  The  view  at  Fig.  326-A 
shows  the  method  of  milling  a  bevel  pinion.  At  B  the  gear  cutting 
attachment  is  removed  and  a  vise  is  supplied  to  hold  work  machined 
by  a  facing  cutter  driven  directly  from  the  lathe  spindle.  The 
view  at  C  shows  the  attachment  rigged  up  for  milling  flutes  in 
a  reamer.  Obviously  a  device  of  the  character  will  prove  very 
valuable  in  any  small  machine  shop  where  a  regular  universal  mill- 
ing machine  is  not  available. 

Another  milling  attachment  for  lathes  is  shown  at  Fig.  327. 
This  is  made  by  the  Cincinnati  Pulley  Machine  Company  and  is 
capable  of  using  standard  cutters  and  doing  such  work  as  Woodruff 
keyseats,  key  ways,  surface  and  end  milling,  slotting,  etc.  The 
machine  is  furnished  with  a  J  H.  P.  motor  which  is  geared  to  a 
worm  gear  driving  the  cutter  spindle  so  the  ratio  of  72  to  1  gives 
ample  power  for  all  average  work.  The  motor  is  attached  to  any 
lamp  socket  by  cord  and  is  then  ready  to  operate. 

They  are  furnished  for  either  direct  or  alternating  current  and 
wound  for  either  110  or  220  volts.  The  spindle  is  made  of  high 
carbon  steel  and  runs  in  bronze  bearings.  The  worm  is  of  steel, 
hardened  and  ground.  The  worm  wheel  is  made  of  bronze.  The 
worm  and  worm  wheel  runs  in  an  oil  container,  the  cover  of  which 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     437 


Cutter         Bevel  Pinion  Blank 


Tkcin 
Cutter 

N. 


A 


B 

Letthe  Bed 


Headstoc 


Reamer 
Drive  Gear  Work  Support 


FIG.  32(3.  —  Outlining  Some  Practical  Applications  of  the  Barnes  Milling 
Attachment  for  Lathes. 


438  MODERN  LATHE  PRACTICE 

is  removed  in  illustrations  to  show  gearing.  Annular  ball  bearings 
are  employed  on  both  worm  and  worm  gear  shafts  to  reduce  friction. 
The  illustrations  show  very  clearly  the  round  column  on  which 
the  sliding  arm  is  carried.  This  arm  is  provided  with  a  vertical 
adjustment  to  raise  or  lower  the  cutter  according  to  the  work  to 
be  done.  The  vertical  screw  connected  with  the  arm  permits 
micrometer  adjustment.  Cross  and  longitudinal  adjustment  is 
taken  care  of  by  the  carriage  and  cross  feed  movements  of  the 
lathe.  The  cutter  in  illustration  A  is  milling  a  squared  shaft  and 
various  samples  of  work  that  can  be  done  with  the  device  are  also 
shown  here.  The  desired  longitudinal  movement  of  the  cutter  is 
obtained  by  hand  movement  of  the  lathe  carriage.  The  shaft  is 
supported  by  the  lathe  chuck  and  tail  stock  center.  In  the  view 
B  the  cutter  is  shown  at  work  on  a  male  driving  clutch  member 
which  is  supported  by  the  lathe  chuck.  The  method  of  using  the 
attachment  is  clearly  shown  in  illustrations.  An  indexing  mechan- 
ism is  also  furnished  by  the  makers  to  permit  the  device  to  cut 
gears.  The  driving  motor  speed  is  1700  R.  P.  M.,  the  cutter 
spindle  speed  is  24  R.  P.  M. 

KNURLING  ON  THE  LATHE 

Knurling  is  very  easily  accomplished  on  any  lathe  if  the  right 
tools  are  available.  The  illustration,  Fig.  328-A,  shows  a  piece 
of  steel  with  three  different  grades  of  knurling.  The  knurling  tool 
for  doing  the  work  is  shown  at  B  and  is  intended  to  be  held  in  the 
tool  post  in  the  same  manner  as  a  cutting  tool.  The  piece  to  be 
knurled  is  driven  slowly  on  centers  or  held  in  the  chuck  and  the 
tool  is  forced  slowly  into  the  revolving  work.  This  revolves  the 
knurling  wheels  and  produces  the  desired  effect.  The  knurling 
wheels  are  hardened  and  it  is  necessary  to  use  oil  plentifully  during 
the  operation.  The  tool  shown  at  C  is  a  novel  one  and  is  very 
easily  made  by  any  machinist.  A  pair  of  cheap  pliers  with  soft 
jaws  are  purchased  and  milled  for  the  knurling  wheels.  While 
a  pair  of  parallel  jar  pliers  are  best,  the  ordinary  forms  will  do  very 
well.  The  pressure  for  knurling  is  produced  by  a  wing  nut  as 
indicated.  A  tool  of  this  nature  will  be  found  valuable  in  knurling 
small  work  where  the  tool  shown  at  B  cannot  be  used  on  account 
of  the  spring  of  the  stock. 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION  439 


440 


MODERN  LATHE  PRACTICE 


INDICATORS  AND  THEIR  USE 

The  old  and  almost  universally  used  method  of  trueing  up 
work  in  a  lathe  chuck  or  when  held  on  centers  by  using  a  piece  of 
chalk  to  indicate  the  high  spots  is  only  good  for  the  first  adjustment 
of  rough  work.  For  trueing  up  work  where  the  finish  must  be 
accurate,  test  indicators  have  been  devised  which  show  minute 
variations  from  truth  of  running  in  an  unmistakable  manner. 
Two  forms,  and  the  method  of  using  them,  are  shown  at  Fig.  329. 


fi 


Knurl  intf 
Wheels 


Coarse  Medium  Fine 


•Knurling  Wheels 


B 


Tool  Body 


Pressure 
Screw 


FIG.  328.  — Tools  for  Knurling  in  the  Lathe. 

The  "Last  Word"  test  indicator  at  A  employs  a  dial  gauge  and 
enclosed  multiplying  mechanism,  the  Starrett  device  at  C  has  a 
simple  multiplying  lever  and  one  end  of  the  lever  serves  as  a  pointer 
to  mark  the  error  on  the  scale  carried  on  the  body  of  the  device. 
The  gauge  at  A  is  shown  installed  on  a  ball  joint  tool  post  shank. 
The  auxiliary  clamp  provided  with  this  instrument  to  permit  of 
setting  it  up  on  the  scriber  member  of  a  surface  gauge  at  B  is  also 
shown  at  A. 

The  ball  joint  connection  between  the  tool  post  shank  and  the 
indicator  makes  it  possible  to  apply  the  device  to  a  great  variety 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     441 


of  work.  The  contact  lever  has  a  hardened  taper-head  stud  for 
bearing,  which  provides  adjustment  for  wear.  There  is  a  small 
tapered  hole  through  the  contact  ball,  and  contact  points  of  special 
shape  can  be  fitted  into  this  hole  to  meet  the  requirements  of  special 
classes  of  work.  In  many  cases  the  ordinary  contact  ball  is  quite 
satisfactory  without  providing  any  auxiliary  point.  The  mechan- 


ForUse-lnTgplPdst 


ft 

Scale        AuxiliaryCIa 


indicator  Point        Indicator 
Fulcrum 


FIG.  329.  —  Indicators  and  Their  Use. 

ism  of  this  indicator  has  been  worked  out  to  give  the  magnifying 
power  of  100,  and  at  the  same  time  the  instrument  is  of  remarkably 
small  size,  which  will  be  appreciated  when  it  is  known  that  the 
weight  is  only  1£  ounce.  The  dial  is  graduated  to  read  in  0.001 
inch.  This  instrument  can  be  quickly  changed  from  the  tool  post 
shank  to  the  needle  of  a  surface  gauge  to  adapt  it  for  surface  plate 


442  MODERN  LATHE  PRACTICE 

work  or  back  to  the  tool  post  shank  for  lathe,  shaper,  planer,  grind- 
ing or  milling-machine  work.  It  is  adaptable  for  use  on  a  great 
variety  of  tool  room  and  machine-shop  operations. 

The  Starrett  indicator  is  also  light  and  very  simple  in  construc- 
tion. The  indicating  lever  is  so  proportioned  that  it  will  multiply 
the  error  about  15  times  which  is  sufficient  for  all  ordinary  work. 
The  method  of  using  the  indicator  is  so  clearly  outlined  at  D  that 
no  further  description  is  necessary.  Many  other  uses  for  a  device 
of  this  nature  will  suggest  themselves  to  the  practical  workman. 


BORING  BAR  CONSTRUCTION  AND  USE 

The  lathe  is  often  used  for  boring,  or  internal  turning  and  is  as 
well  adapted  for  that  class  of  work  as  it  is  for  the  plainer  and 
easier  external  work.  The  simpler  operations  of  boring,  such  as 
holes  that  are  too  large  to  be  drilled  economically,  can  be  performed 
with  a  simple  design  boring  tool  that  can  be  attached  directly  to 
the  tool  post.  A  hole  is  first  drilled  in  the  piece  of  sufficient  size 
to  accommodate  the  boring  tool,  the  work  then  going  on  just  as  in 
external  turning  as  far  as  control  of  the  tool  is  concerned.  Special 
boring  tools  and  supporting  fixtures  are  necessary  when  the  work 
demands  and  while  the  simple  forged  tool  does  good  work  in  the 
smaller  sizes,  it  is  believed  to  be  more  economical  to  use  tool  holders 
with  removable  high  speed  steel  tools  on  the  heavier  work. 

The  boring  fixture  shown  at  Fig.  330-A  is  an  adjustable  design 
for  light  work.  The  boring  tool  is  supported  in  a  swinging  tool 
holder  held  at  one  end  by  a  fulcrum  screw,  and  the  whole  is  sup- 
ported in  a  frame  adapted  to  be  secured  to  the  tail  stock  spindle. 
The  amount  of  stock  removed  at  a  cut  is  regulated  by  the  adjusting 
screws  passing  through  the  sides  of  the  tool  support  frame,  these 
permitting  the  boring  tool  to  be  brought  in  contact  with  the  work 
with  varying  degrees  of  pressure.  The  boring  tool  is  of  round 
stock  and  is  kept  in  place  in  the  socket  made  to  receive  it  in  the 
tool  holder  by  clamping  screws. 

Another  design  in  which  the  cross  slide  of  the  lathe  is  used  to 
support  the  boring  bar  is  shown  at  Fig.  330-B.  The  tool  support 
is  of  round  stock,  having  a  hole  drilled  through  one  end  at  an 
angle.  The  cutter  is  made  of  high  speed  steel,  round  section  and 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     443 


is  a  good  fit  in  the  hole  of  the  tool  holder.  A  taper  pin  is  provided 
to  lock  the  cutter  in  the  holder.  The  boring  bar  itself  is  held  by  a 
cast  iron  clamp  member  attached  to  the  cross  slide  carriage  instead 
of  the  usual  tool  post  by  bolts.  The  cutter  or  boring  tool  may  be 


Adjusting  5crew 
n 

Tool  Support  Frame 


UtheChuck 


Boring  Toot 


Tail5tocK 
V      5pindle 

Adjusting  Screw 


Tool  Suppoft 
Casting 


FIG.  330.  — Boring  Bar  Construction  and  Use. 

removed  for  regrinding  by  knocking  out  taper  pin  which  releases 
the  tool  from  its  socket  in  the  tool  holder. 

Two  designs  of  boring  bars  for  heavy  work  are  shown  at  Fig. 
331.  That  at  A  uses  an  adjustable  boring  tool  which  can  be  moved 
out  by  loosening  the  clamping  screws  and  screwing  in  the  adjusting 


444 


MODERN  LATHE  PRACTICE 


screw.  The  tool  support  casting  may  be  attached  to  the  cross- 
slide  of  the  lathe  as  indicated  at  Fig.  330-B.  The  boring  bar  at 
B,  Fig.  331,  is  similar  in  principle  to  that  shown  at  A  as  relates  to 
manner  of  support.  The  cutter,  however,  is  of  rectangular  section 
stock,  has  two  cutting  edges  and  is  intended  to  make  the  desired 
hole  with  one  cut.  The  cutter  is  held  in  place  in  cutter  support 
by  a  locking  wedge.  This  form  of  boring  bar  is  more  suitable  for 
finishing  and  duplicate  boring  where  it  is  desirable  to  have  the 
bore  come  to  the  size  determined  by  the  cutter.  Cutter  supporting 
bars  or  boring  bars  of  the  form  at  A  and  B,  Fig.  331,  are  used  more 
in  manufacturing  than  general  work.  They  are  also  widely  used 
in  boring  mills  and  turret  lathes. 


I 


rfl 


Lathe  Chuck 


R 

Adjustirg  Screw 


•Lathe  Chuck 


I 


Tool  Support  I  f 

""TSFL 


Tool  Support 
Casting 


Tool  Support 
Castin 


FIG.  331.  — Boring  Bars  for  Heavy  Work. 


SPECIAL  METHODS  OF  HOLDING  WORK 

While  it  is  not  difficult  to  chuck  pieces  of  regular  form  or  to 
secure  them  to  the  lathe  face  plate,  there  are  many  machining 
operations  that  call  for  special  methods  of  holding  the  work,  es- 
pecially on  machinery  used  in  manufacturing.  In  a  job  shop  doing 
only  repair  work,  each  job  is  different  and  many  extemporized 
fixtures  are  designed  and  fitted  up  which  are  dismantled  and 
thrown  to  one  side  when  the  work  is  done.  In  manufacturing, 
which  means  turning  out  a  number  of  duplicate  pieces,  an  invest- 
ment in  accurate  fixtures  of  a  permanent  character  is  justified. 

Various  methods  of  holding  pieces  not  ordinarily  met  with  in 
regular  work  are  shown  at  Figs.  332  and  333.  These  will  prove 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     445 


446 


MODERN  LATHE  PRACTICE 


valuable  in  suggesting  ways  other  pieces  of  similar  form  may  be 
held.  The  fixture  at  A  is  made  of  cast  iron  and  is  bolted  to  the 
lathe  face  plate.  It  is  designed  to  support  gas  engine  pistons 
when  it  is  desired  to  bore  the  hole  through  the  bosses  for  the  wrist 
pin.  The  piston  is  properly  located  in  the  bosses  of  the  fixture 
made  to  receive  it  and  firmly  clamped  in  place.  The  hole  is  first 
drilled  through  the  bosses,  after  which  a  reamer  is  used  to  finish 
the  hole.  It  is  apparent  that  any  body  of  cylindrical  form  could 
be  held  by  similar  means. 

It  is  often  desirable  to  turn  the  outside  diameter  of  cylindrical 
bodies  having  light  section  walls.  One  end  is  often  designed  with 
a  flange  so  it  can  be  attached  to  the  lathe  face  plate,  but  the  problem 


Chuck  Body         Plungers  5top  Piston  Bosses 


Tftneac 


•Expanding 


End  View 
Gas  Engine  Piston 


FIG.  333.  —  Special  Chuck  for  Gas  Engine  Piston  Support. 

is  to  supporj;  the  other  end  if  the  piece  is  long.  A  revolving  spider 
for  live  tail  stock  center  well  adapted  for  work  of  this  character  is 
shown  at  B.  The  main  portion  of  the  device  or  body  is  of  cast 
iron  and  is  provided  with  a  bronze  bearing  which  runs  on  the 
taper  bearing  of  the  shank  adapted  to  be  held  by  the  tail  stock 
spindle.  Provision  is  made  to  take  the  end  thrust  on  a  suitably 
beveled  shoulder  on  the  shank  or  axle.  The  spider  body  is  pro- 
vided with  three  holes  in  which  plungers  fit.  These  have  their  lower 
ends  beveled  to  fit  the  taper  on  the  adjusting  screws  and  are  kept 
from  turning  by  small  set  screws  working  in  keyways  in  the  plungers 
as  indicated.  The  outer  portions  of  the  plungers  are  rounded  off. 
To  hold  the  piece  securely,  it  is  only  necessary  to  screw  in  the 
adjusting  screws  and  raise  the  plungers  into  contact  with  the  inner 
periphery  of  the  metal  ring.  As  the  screws  can  be  turned  inde- 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     447 

pendently  it  is  possible  to  hold  the  piece  firmly,  yet  accurately. 
A  fixture  of  similar  design  may  be  made  to  hold  light  narrow  rings 
by  having  the  body  of  the  device  threaded  to  screw  on  the  nose  of 
the  head  stock  spindle  or  provided  with  bolts  to  fasten  it  to  the 
lathe  face  plate.  In  this  case  it  is  not  necessary  for  the  body  of 
the  device  to  revolve  independently  of  its  supporting  means. 

The  automobile  steering  spindle  shown  at  C  is  another  difficult 
piece  to  machine  because  of  its  irregular  shape  and  also  because 
the  holes  through  the  spindle  body  are  not  at  right  angles  to  the 
spindle.  The  methods  of  supporting  this  piece  for  drilling  the  holes 
and  have  the  spindle  at  the  proper  angle  as  well  as  supporting  the 
piece  to  turn  the  spindle  itself  are  so  clearly  detailed  that  the 
process  may  be  readily  understood  by  even  the  novice  machinist. 

A  special  chuck  for  machining  the  exterior  of  a  gas  engine  piston 
is  clearly  shown  at  Fig.  333.  The  same  wedge  operated  plunger 
principle  previously  outlined  is  shown,  the  novelty  being  in  the 
method  of  operating  the  expanding  wedges  or  cones  simultaneously. 

This  chuck  has  two  sets  of  three  plungers,  one  set  at  the  front 
and  the  other  at  the  rear,  which  true  the  casting  up  so  that  an  even 
thickness  of  wall  is  obtained  in  the  finished  piston.  The  stop 
screw  serves  the  double  purpose  of  holding  the  cover  in  place  and 
locating  the  piston  endwise  so  that  an  equal  thickness  of  head  is 
obtained  on  all  pistons.  The  construction  of  the  chuck,  which  is 
operated  through  the  expanding  cone  by  means  of  a  handwheel  at 
the  back  end  of  the  spindle,  is  clearly  shown  and  needs  no  further 
description.  The  chuck  body  may  be  threaded  to  be  secured  to 
the  head  stock  spindle  nose  if  desired  or  held  in  any  other  manner. 

How  SWING  OF  LATHE  MAY  BE  INCREASED 

In  a  small  shop  where  the  possible  investment  in  machinery  is 
limited,  many  expedients  are  followed  to  fit  machines  to  work  for 
which  they  were  not  primarily  intended.  One  of  the  conditions 
often  confronting  the  small  shop  owner  is  to  swing  larger  work  than 
his  lathes  are  made  for,  and  yet  these  conditions  do  not  occur  often 
enough  to  justify  the  purchase  of  a  larger  lathe.  The  illustrations 
at  Fig.  334  show  two  ways  of  increasing  the  swing  of  a  lathe.  At 
A,  the  method  of  using  raising  blocks  to  enable  a  15-inch  lathe  to 
swing  20  inches  over  the  bed  is  shown.  The  raising  block  equip- 


448 


MODERN  LATHE  PRACTICE 


ment  includes  blocks  for  head  stock,  tail  stock,  tool  rest  and  center 
rest  as  well  as  necessary  bolts  for  attaching  blocks  to  lathe.  These 
can  be  procured  from  the  lathe  manufacturer  in  many  cases. 

The  gap  bed  lathe  is  a  popular  machine  tool  for  jobbing  and 
repair  shops,  and  the  combination  of  the  gap  bed  and  lifting  blocks 


Headstock 


Raising  Block 


Tailstock 


Large  Flywheel 
Raising  Block 


Raising 
Block 


FIG.  334.  —  Methods  of  Increasing  Swing  of  Lathe  Outlined. 

as  shown  at  B  enables  the  machinist  to  do  many  jobs  of  repair 
work  he  would  ordinarily  be  obliged  to  turn  away.  With  a  gap 
bed  lathe,  if  a  job  of  large  diameter  comes  in,  it  is  a  simple  matter 
to  remove  the  bridge  from  the  bed  and  swing  the  work.  If  opening 
the  gap  does  not  provide  sufficient  space,  the  raising  blocks  may 
be  used  as  well. 

In  this  manner,  a  lathe  capable  of  swinging  but  15  inches 
with  bridge  in  place  may  be  able  to  swing  nearly  twice  that  much 
with  the  raising  blocks  inserted  and  gap  bridge  removed. 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     449 


LATHES  FOR  HEAVY  WORK 

Some  of  the  refinements  of  detail  noted  in  the  Lodge  &  Shipley 
lathes  for  heavy  cuts  are  shown  at  Fig.  335  as  being  of  interest  to 
the  student  of  lathe  construction.  A  light  bridge  will  answer  for 


Lathe  Bed 


Clamp 
Bolts 


FIG.  335.  —  Lathe  Construction  for  Heavy  Cuts. 

light  cuts  on  large  diameters  with  the  tool  point  directly  above  the 
front  shear.  But  stresses  are  of  a  very  different  sort  when  the 
lathe  is  under  a  heavy  cut  on  a  small  diameter. 

The  illustration  A  shows  the  position  of  tool  and  compound 


450  MODERN  LATHE  PRACTICE 

rest  on  the  24  inch  Patent  Head  lathe  when  taking  a  15  H.  P.  cut 
on  work  of  5  inches  diameter.  Heavy  arrow  indicates  direction  of 
pressure  due  to  cut.  Note  the  large  bearing  against  the  top  and 
inside  of  bed  directly  in  line  with  the  tool  thrust,  in  addition  to 
the  full  length  bearing  of  carriage  upon  front  and  rear  Vs.  This 
extra  bearing  gives  a  solid  support  to  the  bridge  just  where  it  is 
needed,  and  positively  prevents  a  deflection  or  distortion  even 
under  the  heaviest  cuts. 

The  sectional  illustration  at  B  shows  why  the  tail  stock  will 
not  back  away  from  the  work,  no  matter  how  heavy  the  cut.  A 
pawl  which  engages  the  rack  cast  in  the  center  rib  of  the  bed  fur- 
nishes a  positive  brace  against  end  thrust.  The  four  bolts  for 
clamping  the  tail  stock  to  the  bed  extend  to  the  top  of  the  barrel, 
where  the  nuts  are  easily  accessible;  and  because  of  this  construc- 
tion the  whole  tail  stock  is  drawn  down  solidly  and  evenly  against 
the  bed.  The  tail  stock  is  massive  in  proportions  and  has  long 
bearing  on  the  bed.  The  barrel  is  large  and  permits  long  travel  of 
the  spindle.  Floating  plug  binders  lock  the  tail  stock  spindle 
securely  and  in  correct  alignment.  The  tail  stock  barrel  is  not 
split,  but  is  always  a  correct  reamed  fit  for  the  spindle. 


GRINDING  ATTACHMENTS  FOR  LATHE 

In  the  absence  of  a  grinding  machine  many  repair  shops  com- 
plete repairs  by  boring  and  turning,  when  a  fine  degree  of  accuracy 
would  be  advisable.  Many  owners  of  small  shops  do  not  care  to 
go  to  tKe  expense  of  installing  grinding  machines  although  desiring 
their  use.  In  accompanying  illustration,  Fig.  336,  a  grinding 
attachment  is  shown,  that  the  designer  states  may  be  attached  to 
any  engine  lathe  of  sufficient  center  capacity. 

The  grinder  itself  is  carried  by  a  slab  and  studshaft,  the  arm 
of  which  is  about  1.75  inches  in  diameter,  so  as  to  insure  the  neces- 
sary rigidity.  The  slab  is  attached  to  the  face  plate  of  the  lathe  by 
means  of  two  .75  inch  bolts,  of  which  the  top  one  is  arranged  in  a 
radial  slot,  to  facilitate  adjustment  of  the  work  in  hand.  Upon  the 
arm  of  the  studshaft  is  mounted  a  length  of  solid  drawn  hydraulic 
tubing,  which  revolves  on  two  brass  bushings  forced  and  sweated 
into  the  ends  of  it,  thus  leaving  an  annular  space  for  the  lubricant. 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     451 


The  tube  carries  a  driving  pulley  on  its  inner  end,  the  grinding 
wheel  being  attached  to  the  outer  end.  The  driving  pulley  is 
secured  to  the  tube  by  means  of  two  set  screws.  This  pulley  is 
fitted  with  a  sufficiently  convex  face,  in  order  to  eliminate  lateral 
slip  of  the  belt.  The  outer  end  of  the  tube  is  threaded  to  receive 
a  thimble  which  is  screwed  and  sweated  into  place. 

Owing  to  the  path  which  the  wheel  spindle  follows  the  use  of 
a  floating  countershaft  is  necessary.  The  connecting  rod  to  the 
latter  is  shown  broken  off  in  the  lower  illustration  and  the  ar- 


Pulley 
Face  Plat- 


Floating 
Countershaft 

End  View 

Emery  Wheel 


FIG.  336.  —  Grinding  Attachment  for  Lathe  Using  Floating  Countershaft 

rangement  of  the  floating  countershaft  is  depicted  in  the  upper 
drawing.  As  previously  mentioned  the  feed  of  the  grinding  wheel 
is  adjusted  by  the  bolt  situated  in  the  radial  slot  while  the  travel 
is  supplied  by  the  lathe  slide  rest. 

Some  machinists  display  considerable  ingenuity  in  building 
grinding  attachments  for  the  lathe  and  such  a  device  is  shown  at 
Fig.  337.  It  will  be  noted  that  the  design  does  not  employ  a 
floating  countershaft.  With  it  the  inventor  claims  he  is  able  to 
grind  hardened  steel  spindles,  camshafts,  crankpins,  valves,  cylin- 
ders, etc.,  and  states  that  in  planning  the  attachment  considerable 


452 


MODERN  LATHE  PRACTICE 


thought  was  given  to  have  the  equipment  as  rigid  as  possible  and 
that  all  parts  operated  on  with  it  should  be  ground  quite  circular. 
The  maker  states  that  the  attachment  can  be  used  either  for 
grinding  internal  or  external  work  and  that  it  can  be  fitted  easily 
to  the  ordinary  lathe.  The  left  hand  figure  shows  the  end  eleva- 
tion and  that  at  the  right  the  grinding  spindle  and  method  of 
attaching  it  to  the  tool  clamp  of  the  top  portion  of  a  compound 
slide  rest.  The  smaller  figure  shows  a  plan  of  the  grinding  arm  it- 
self, which  is  somewhat  after  the  style  of  a  Landis  grinder.  The 
attachment  can  be  made  fairly  easily,  but  if  desired  can  be  pur- 


Drivir^S  Drum 
Lathe  Hcadstock 


Driving  Drum 
Wheel ,  Wheel. 


Wheel 
i  Support 


FIG.  337.  —  Grinding  Attachment  for  Lathe  Using  Overhead  Drum. 

chased.  For  internal  work  it  is  provided  with  a  long  arm  but  for 
external  work,  the  latter  is  only  about  3  inches  in  length. 

A  small  pulley  for  driving  the  arm  is  seen  located  between  two 
bearings,  so  that  it  will  be  realized  that  there  is  no  overhang  to 
set  up  vibration.  The  method  of  driving  the  spindle  consists  of  a 
countershaft  carrying  a  drum  supported  by  a  pair  of  hangers 
placed  in  front  of  the  ordinary  overhead  shop  shaft  and  about 
central  with  the  lathe,  so  that  the  attachment  can  travel  about  6 
inches  on  either  side  without  materially  altering  the  relative 
position  of  the  driving  belt. 

The  driving  drum  consists  of  two  12-inch  diameter  pulleys 
about  2  inches  wide.  These  are  placed  about  3  feet  apart  and 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     453 

then  lagged  with  strips  of  wood  one  inch  in  width,  these  being 
placed  lengthwise  and  attached  to  the  pulleys  by  means  of  cap 
screws.  The  whole  is  then  skimmed  up  in  a  lathe,  and  it  will  be 
found  that  this  makes  quite  a  nice  light  overhead  drum,  which 
gives  nearly  three  feet  of  travel  over  the  grinding  wheel.  The 
small  pulley  is  so  arranged  that  it  may  be  driven  off  the  existing 
cone  pulley  on  the  overhead  shaft  which  drives  the  lathe.  By  this 
means  a  good  increase  of  velocity  is  given  by  the  emery  wheel. 

The  cut  is  put  on  by  means  of  a  cross  fed  screw  in  the  lathe 
saddle.  If  a  taper  movement  is  required  the  top  rest  is  of  course 
set  to  taper  just  as  if  one  were  going  to  machine  taper  in  the  ordi- 
nary way.  The  maker  of  the  attachment  states  that  he  considers 
the  rig  simple,  that  it  will  provide  accuracy  in  grinding,  and  can  be 
fitted  by  any  average  machinist. 


MACHINING  CONCAVE  AND  CONVEX  SURFACES 

Considerable  ingenuity  is  displayed  by  automobile  repairmen 
in  overcoming  various  machining  difficulties,  and  an  instance  of  a 
useful  lathe  attachment  is  described  in  a  current  issue  of  the  Com- 
mercial Motor,  an  English  publication.  The  repairman  had 
occasion  to  replace  parts  of  a  badly  damaged  torque  tube  and 
ball  universal  joint  and,  when  he  came  to  turn  the  ball  and  its 
seating,  was  confronted  by  a  problem,  inasmuch  as  the  only  machine 
available  was  a  12-inch  center  lathe. 

The  sketches  at  Fig.  338  show  the  attachment  constructed  and 
applied,  and  demonstrates  how  the  concave  and  convex  surfaces 
required  were  turned.  The  upper  drawing  shows  the  attachment 
for  turning  the  concave  surface;  the  lower  depicts  the  ball  being 
machined.  The  diagram  underneath  each  lathe  illustrates  the 
path  of  the  cutting  tool.  The  attachment  consisted  of  flat  mild 
steel  strips,  the  sections  being  .5  inch  by  1  inch.  Six  lengths 
were  cut  off  to  obtain  the  necessary  travel,  and  at  the  base  of  the 
angle  pieces  were  drilled  two  .375-inch  diameter  holes.  The  plain 
ends  were  drilled  out  .5  inch. 

The  swiveling  connecting  rods,  two  in  number,  were  drilled 
out  and  tapped  .5  inch  Whitworth  at  each  end,  the  centers  being 
carefully  marked  out  equal  to  the  radius  of  the  ball  and  spherical 


454 


MODERN  LATHE  PRACTICE 


seating;  that  is,  four  inches.  Permitting  these  to  swing  at  the  end 
of  each  angle  piece  enabled  the  necessary  arc  of  the  cutting  tool 
to  be  effected. 

It  will  be  noted  that  for  either  machining  operation,  one  angle 
strip  is  bolted  to  the  tail  stock  of  the  lathe,  and  another  piece  to  the 
top  slide  under  the  tool  rest.  Cross  feed  only  is  used,  the  trans- 
verse feed  being  free  altogether  so  that  without  touching  the  hand- 


*=${i   .M  ii 

ht'4 


fl 


FIG.  338.  —  Device  for  Machining  Concave  and  Convex  Surfaces  on  Lathe. 
A— Path  of  Cutting  Tool  for  Ball  Seating.  B  — Swivelling  Links  for 
Securing  Radii.  C — Path  of  Cutting  Tool  for  Sphere. 

wheel  the  carriage  may  readily  be  pushed  along  the  lathe  bed. 
The  cutting  tool  may  then  be  made  to  follow  the  required  circular 
path. 

GROOVING  OIL  DUCTS  ON  LATHE 

Cutting  oil  grooves  in  bearings  with  a  chisel  is  not  always  a 
satisfactory  method  and  considerable  time  is  lost  in  the  operation. 
The  proper  method  is  to  utilize  an  oil  grooving  machine,  but  these 
are  not  common  in  repair  shops.  An  attachment  for  an  ordinary 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     455 

lathe  which  the  repairman  who  constructed  the  device  states  can 
be  utilized  to  groove  any  size  bush  or  bearing  is  shown  at  Fig. 
339.  The  drawing  is  practically  self-explanatory  but  the  chief 
points  to  be  considered  are  that  the  arrangment  should  be  bolted 
firmly  to  the  lathe  body  and  that  the  adjustable  arm  connecting 
the  carriage  with  the  horizontal  disc  should  be  parallel  with  the 
lathe  bed  at  each  end  of  its  stroke. 


t.r-L, 


FIG.  339.  —  Attachment  for  Grooving  Bearings  on  Lathe.  A  —  Grooved 
Brass  in  section.  B — Arrangement  of  Drive.  C  —  The  Work  in  Chuck. 
D — Disc  Drilled  to  Give  Various  Strokes.  E  — Adjustable  Connect- 
ing Rod.  F  —  Screw  Which  is  Removed  to  Allow  for  Free  Travel  of 
Tool. 

The  screw  in  the  carriage  holder  must  be  withdrawn  before 
commencing  operations,  so  as  to  enable  the  carriage  to  slide  easily 
in  either  direction.  The  drive  must  be  so  proportioned  as  to 
enable  the  chuck  to  make  one  revolution  while  the  tool  is  traveling 
the  whole  length  of  its  stroke.  An  oil  groove,  after  the  outline  of 
that  shown  in  the  small  sketch,  will  thus  be  made  to  feed  oil  equally 
all  over  the  bearing. 


456  MODERN  LATHE  PRACTICE 

For  example:  Assume  that  a  bush  1.5  inches  long  is  to  be 
grooved.  The  pin  on  the  horizontal  disc  is  set  .625  inch  out  of 
center;  the  connecting  rod  adjusted  and  the  main  carriage  bed 
locked.  The  transverse  screw  is  then  removed  from  the  tool 
carriage  and  the  grooving  tool  set  about  .125  inch  inside  the  bush, 
and  the  lathe  started. 

The  carriage  being  free  to  slide,  the  connecting  rod  will  cause 
the  tool  to  travel  just  1.25  inches,  and  the  gearing  being  so  ar- 
ranged that  the  chuck  will  make  one  revolution  during  the  complete 
travel  of  the  tool,  an  oil  groove  of  the  required  length  and  pitch 
will  be  cut  into  the  bearing. 


USE  OF  COMBINATION  LATHE  DOGS 

Sometimes  in  the  overhaul  it  is  found  that  the  crankpin  is  worn 
oval  and  will  not  yield  to  ordinary  methods,  and  when  such  is  the 
case  a  light  cut  is  taken.  The  Stras burger  Manufacturing  Com- 
pany is  marketing  combination  lathe  dogs,  which  are  shown  at 
Fig.  340  and  these  members  are  adjustable  from  2  to  6  inches. 
They  are  designed  for  holding  all  kinds  of  crankshafts,  such  as 
utilized  in  automobile  and  marine  engines,  and  other  power  plants, 
and  can  be  employed  wherever  a  common  lathe  dog  can  be  used. 

The  design  illustrated  at  D  is  adapted  for  turning  heavy  work 
such  as  motor  truck  engine  crankshafts,  and  is  adjustable  from 
two  to  eight  inches.  It  is  provided  with  a  screw  feed  center  and 
gauge,  and  each  type  of  dog  is  constructed  of  the  best  malleable 
iron  with  case  hardened  steel  screws. 

The  company  points  out  that  the  turning  up  of  a  crankshaft 
has  always  been  accomplished  under  certain  difficulties  except  in 
shops  where  they  are  made  in  large  numbers,  and  where  special 
machines  are  required.  As  crankshafts  are  now  forged  in  nearly 
all  sizes  and  forms,  and  may  be  procured  at  a  reasonable  cost  in 
the  rough,  it  is  possible  to  turn  these  up  in  the  lathe  by  the  follow- 
ing process: 

Assuming  that  a  four-throw  crankshaft  is  to  be  finished,  although 
single  and  double  ones  are  more  common  to  the  average  repairman 
of  marine  engines.  The  first  step  is  to  center  the  work,  either  by 
laying  off  and  centering  in  the  drill  press  or  in  the  lathe  with  the 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION     457 

use  of  a  steady  rest.     The  driving  dog  is  fastened  at  one  end  and 
the  work  placed  between  centers. 

The  bearings,  front,  center  and  rear,  are  roughened  down  to 
within  .065  inch  of  the  finished  size.  The  straight  or  tailless  dog 
is  then  fastened  on  the  other  end  and  one-half  of  the  stroke  is 
measured  from  the  center  of  the  crank  to  the  center  hole  in  the 


---OH 


FIG.  340. — How  to  Use  Combination  Lathe  Dogs  for  Turning  Up 
Crankshaft. 

adjustable  screws  and  the  nuts  securely  tightened.  The  work  is 
then  placed  between  the  adjustable  centers  and  lined  up  parallel 
by  running  the  lathe  carriage  back  and  forth. 

The  second  and  third  pins  should  be  roughened  down  to  within 
.0625  inch  of  the  finished  size.  The  dogs  should  now  be  loosened 
and  the  crank  given  half  a  turn,  the  first  and  fourth  pins  lined  up 
parallel,  and  finished  to  exact  size.  After  this  is  done  the  dogs 


458  MODERN  LATHE  PRACTICE 

are  again  loosened  and  the  crank  given  half  a  turn  back  and  lined 
up  parallel  to  finish  the  second  and  third  pins  to  exact  size. 

The  four  pins  are  now  finished  to  size,  so  the  straight  dog  and 
the  counter-balance  should  be  taken  off,  and  the  crank  placed 
between  centers.  The  center  bearing  is  then  finished  to  size  and 
the  steady  rest  applied,  while  the  front  and  rear  bearings  are  being 
finished  to  size.  Care  should  be  taken  not  to  have  the  tail  stock 
center  too  tight  during  the  finishing  cuts. 

The  large  face  plate  should  be  used  for  this  operation  and  a 
weight  clamped  to  it  for  a  counter-balance.  If  the  crank  should 
have  a  flange  on  one  end,  it  may  be  chucked  and  a  four-jaw  chuck 
used  instead  of  the  face  plate,  then  only  one  dog  will  be  necessary. 
If  a  heavy  cut  is  desired  or  the  tool  should  chatter,  the  steady  rest 
can  be  used  on  one  pin,  while  the  other  pin  is  being  turned  down. 


HACKSAW  ATTACHMENT  FOR  LATHES 

A  simple  power  hacksaw  attachment  that  can  be  used  in  connec- 
tion with  this  versatile  machine  tool  is  shown  at  Fig.  341  and  its 
utility  in  the  small  shop  where  such  a  device  does  not  form  part  of 
the  regular  equipment  can  be  readily  understood. 

The  attachment  consists  of  the  side  bar  A  to  which  the  hacksaw 
frame  is  attached,  and  the  guide  bars  or  supports  B  and  C  that 
are  firmly  attached  to  the  base  piece  F.  The  bar  A  is  worked  back 
and  forth  by  a  connecting  rod  E,  that  is  adapted  to  be  attached 
to  the  face  plate  of  the  lathe.  The  small  bar  D  is  a  guide  piece 
to  keep  the  saw  frame  from  turning. 

The  device  is  simple  to  build  and  the  materials  entering  into 
its  construction  are  not  costly;  in  fact  the  design  is  such  that  it 
may  be  easily  placed  on  or  detached  from  the  shears  of  the  lathe. 
The  base  plate  F  is  composed  of  a  cast  iron  slab  one  inch  thick, 
eight  inches  wide,  and  about  five  feet  long.  It  is  possible  to  form 
the  guide  members  B  and  C  integral  when  the  slab  is  cast  if  they 
are  placed  on  the  pattern.  The  slide  is  a  flat  piece  of  steel  .375 
inch  thick  and  two  inches  wide,  the  length  is  about  four  feet,  though 
this  will  vary  according  to  the  stroke. 

A  hole  is  drilled  in  the  center  of  the  bar  for  a  .5-inch  bolt,  which 
is  to  form  the  crankpin  for  the  lower  end  of  the  connecting  rod 


PRACTICAL  INSTRUCTIONS  ON  LATHE  OPERATION    459 


E.  The  supports  B  and  C  may  be  made  of  one-inch  square  ma- 
chinery steel.  The  support  B  has  an  end  turned  and  threaded 
to  suit  a  .75-inch  tapped  hole  made  in  the  cast  iron  base  F.  The 
support  C  may  be  attached  in  a  similar  manner  or  bolted  to  the 
other  end  of  the  base  as  shown.  Each  support  has  a  .375-inch 
slot  cut  through  the  center,  this  being  made  just  large  enough  to 


12  Inch  Bolt 


Saw  Frame 


Couedinf  Rod 


FIG.  341.  —  Simple  Power  Hackshaw  Attachment  for  Lathes. 

permit  an  easy  sliding  fit  to  exist  between  the  slide  bar  and  the 
sides  of  the  guide  members. 

The  smaller  guide  D  is  made  of  .375-inch  by  one-inch  machin- 
ery steel,  one  end  being  bolted  or  riveted  to  the  saw  frame,  allowing 
the  other  end  to  slide  through  the  support  B,  thus  eliminating 
any  tendency  of  the  saw  frame  to  wabble.  The  connecting  rod 
E  is  a  strip  of  .375  steel  about  two  inches,  wide  and  of  a  length  to 
suit  that  of  the  saw  frame,  which  obviously  determines  the  per- 
missible stroke.  The  connecting  rod  is  drilled  at  both  ends  for 


460  MODERN  LATHE  PRACTICE 

.5-inch  bolts,  and  is  intended  to  be  attached  to  the  face  plate  of 
the  lathe  at  the  upper  end  and  the  slide  bar  A  at  the  lower  end. 
The  upper  end  may  be  moved  to  some  extent  in  the  slot  of  the 
face  plate,  making  it  possible  to  vary  the  stroke  within  the  limits 
allowed  by  the  slot  and  the  size  of  the  attachment.  The  saw 
frame  is  forged  of  machinery  steel  and  the  blade  is  made  tight  in 
the  usual  manner,  by  a  thumb  screw  at  the  outer  end  of  the  frame. 
An  ordinary  drill  or  shaper  vise  is  clamped  to  the  base  plate,  this 
to  hold  the  stock  that  is  to  be  cut  off.  The  attachment  is  bolted 
to  the  shears  of  the  lathe  by  a  clamping  bar  under  them,  which  is 
pressed  into  engagement  by  a  .75-inch  bolt  as  depicted. 


INDEX 


Adjustable  conical  front  bearing,  115. 

straight-edge    for    lathe    testing, 

243. 

Alignment  of  centers,  testing  for,  241. 
Allowable  limits  in  lathe  testing,  251. 
American  Tool  Works  Company's  20- 
inch  engine  lathe,  316. 

Tool   Works    Company's   42-inch 

triple-geared  lathe,  331. 
American    Turret    Lathe    Company's 
turret  lathe,  410. 

Watch  Tool  tail-stock,  139. 
Angles  for  tools,  216,  218. 
Angular  work,  turning,  359. 
Anti-friction  metals,  114. 
Aprons,  143,  145. 

Pratt  and  Whitney,  291. 
Arbors,  hardened,  266. 

making  of,  266. 

or  mandrels,  265. 

press,  Greenard's,  267. 

taper,  266. 

use  of,  267. 

Armstrong  tool-holders,  221. 
Asiatic  wood  turner,  24. 
Attaching  shaft  straighteners,  167. 
Attachments,  classification  of,  52. 

for  backing  off  cutters,  185. 

for  bench  lathe,  365. 

for  grinding,  189. 
•    for  lathes,  176. 

for  lathes,  grinding,  450. 

for  lathes,  hacksaw,  459. 

for  lathes,  milling,  433. 

for    thread    cutting,    the    Rivett- 
Dock,  192. 

for  turning  concave  and   convex 
rolls,  181. 

for  turning  concave  surfaces,  183. 

for  turning  convex  surfaces,  184. 


Author's  design  of  21-inch  engine  lathe, 

296. 

design  of  fiddle-bow  lathe,  26. 
reversing  gear  device,  298. 
21-inch  lathe,  76. 
50-inch  lathe,  electric  drive,  413. 

Back  gear  data,  124. 

gear  ratios,  124. 

geared  lathes,  57. 

geared  lathes,  essentials  of,  58. 

gearing,  calculations  for,  122. 

gearing,  faulty  design  of,  125, 127. 

gearing,   homely  proportions  for, 
133. 

gearing  of  head-stocks,  120. 

gearing  of  head-stocks,  operations 
of,  122. 

rests,  164. 

Backing-off  attachment,  185. 
Balance-wheel,     development    of,     in 
lathes,  28. 

Wheel,  early  used  on  lathes,  27. 
Ball  thrust  bearing,  112. 

turning,  179. 

turning  attachment,  180. 
Bancroft  &  Seller's  change  gear  device, 

59,  194. 

Barnes  milling  attachment,  434. 
Bed  for  lathes,  69,  77. 

for  lathes,  depressed  inside  V's,  79. 
Belt  friction  in  lathe  heads,  346. 

horse-power  transmitted  by,  236. 

in  lathes,  132. 

strain  on  bearings,  avoiding,  344. 
Bench  lathe  tail-stock,  139. 
Blaisdell    carriage,    apron,    and    com- 
pound rest,  146. 

18-inch  engine  lathe,  295, 

tail-stock,  3.38. 


461 


462 


INDEX 


Boring  bars,  281. 

bars  for  a  long  hole,  282. 

bars,  hollow,  284. 

large  cylinders,  the  Author's  de- 
vice, 276. 

tools  for  lathes,  442. 

work  on  the  lathe,  274. 
Box  form  of  lathe  bed,  80. 
Box  housings,  113. 
Boxes  for  spindle,  Reed  form,  288. 
Boycott,  first  in  this  country,  15. 
Braces  for  beds,  81. 
Bradford  16-inch  engine  lathe,  314. 

42-inch  triple-geared  lathe,  327. 

rapid  change  gear  device,  203. 

taper  attachment,  155. 
Brass  lathe,  Fox,  56. 
Bridgford  tail-stock,  141. 

Cabinet  and  cupboard,  90. 

for  lathe  beds,  59. 

for  supporting  lathe  beds,  87. 

future  use  of,  92. 
Calculating  amount  of  taper,  270. 

back  gearing,  122. 
Calculations  for  change-gears,  277. 
Cam  cutting  on  the  lathe,  285. 
Capillary  attraction  in  lubrication,  118. 
Carriages  for  lathes,  143. 

form  of,  84. 
Carver,  Mass.,  Iron  Foundry  in,  1735, 

18. 
Cast  iron  bed,  early  form  of,  86. 

boxes  for  spindle  bearings,  288. 
Castings,  iron,  early  history  of,  in  New 

England,  17. 
Center  grinder,  Hisey-Wolf,  190. 

reaming,  256. 

rests,  164. 
Centering  lathe  works,  256. 

machine,  256. 
Chain  lathe,  the  old,  77. 
Champion  tool-holders,  222. 
Change  gear  devices,  59. 

gear  devices,   Author's  book  on, 
197. 

gear  devices,  classification  of,  195. 
Change  gear  mechanisms,  194. 

gears,  how  listed,  52. 


Change-gears,  use  of,  in  thread  cutting, 

278. 

Changing  speed  of  lathe  spindles,  120. 
Chuck  work,  258. 
Chucking  and  centering  works,  263. 

lathes,  54. 

Chucks,  expanding,  446. 
Cincinnati    Electric    Tool    Company's 

tool  post  grinder,  189. 
Circular  saw  attachment  for  foot  lathe, 

32. 
Clamping    work    to    the     face-plate, 

269. 
Classification  of  change  gear  devices, 

195. 

of  lathe  attachments,  52. 
of  lathes,  52. 
of  lathes,  English,  22. 
of  turret  lathes,  371. 
Clearance  of  tools,  218. 
Clutch,    friction    for    foot-power    ma- 
chines, 33. 

Combination  lathe  dogs,  456. 
Compound  change-gears,  279. 
rests,  143,  145. 

rests  for   concaving   and   convex- 
ing  attachment,  179. 
rests,  New  Haven,  147. 
Concave  surfaces,  attachment  for  turn- 
ing, 183. 
machining,  453. 
Conditions  of  materials  to  be  turned, 

216. 
Cone  diameters,  133. 

pulley  turning  rest,  164. 
speeds,  125. 
steps,  -form  of,  108. 
Conical  front  bearing,  115. 
Convex  and  concave  rolls,  turning  of, 

181. 
and  concave  surfaces,  attachment 

for  turning,  184. 
and  concave  surfaces,  machining, 

176. 

Countershaft    boxes,    self-oiling,    172. 
speed,  225. 

used  with  foot  lathe,  33. 
Countershafts,  170. 
friction,  170. 


INDEX 


463 


Countershafts,  geared,  170,  174. 

two-speed,  170. 

variable  speed,  170,  173. 
Crank-shafts,  machining  methods,  457. 

turning  of,  271. 

Criticism  of  modern  lathes,  148. 
Cross-ties  for  beds,  81. 
Crowning  device  for  pulley   turning, 

360. 

Cushman  chuck,  261. 
Cut-meter,  Warner's,  227. 
Cutting   speeds   for   high-speed   steel 
tools,  230,  232. 

threads,  277. 
Cylindrical  cutters  for  boring  bars,  283. 

Data,  making  record  of,  237. 
Davis  18-inch  engine  lathe,  324. 

tail-stock,  139. 

Day's  work  of  the  early  mechanics,  29. 
Definitions  of  turning,  22. 
Design  of  lathe  head-stocks,  346. 

of  lathe  tools,  217. 
Designing  a  lathe  head-stock,  133. 

lathe  carriages,  143. 

lathe  spindles,  102. 

Development    of    the    balance-wheel 
idea,  28. 

of  manufactures,  20. 
Devices   for   machinery   concave   and 

convex  surfaces,  176. 
Diameters  of  lathe  cones,  133. 
Difficulties  of  lathe  design,  70. 
Distortion  of  work,  269. 
Double-spindle  lathe,  McCabe's,  358. 

threads,  cutting  of,  281. 
Dreses  forming  turret  lathe,  398. 

turret  lathe  for  brass,  395. 
DriUing  in  the  lathe,  430. 

speeds,  227. 

work  on  the  lathe,  274. 
Drivers  for  lathes,  258. 

mechanism  of  a  triple-geared  lathe, 

123. 
Driving  feeding  mechanism,  134. 

lathe  work,  257. 

the  lead  screw,  135. 
Dynamometers  and  the  transmission 
of  power,  237. 


Earliest  form  of  lathe,  23. 
Early  development  of  machine  tools, 
20. 

history  of  the  lathe,  21. 

lathe  rests,  25. 

manufactures,  15. 

mechanic,  tools  of  the,  17. 

New  England  factories,  16. 
Electric  drive,  advantages  of,  405. 

designed  by  the  Author,  413. 

simplicity  desirable,  416. 
Electrically  driven  lathes,  405 
Elementary  form  of  lathe  bed,  72. 
Engine,  definitions  of,  286. 

lathe,  286. 

lathes,  complete,  57. 
English  classification  of  lathes,  22. 

form  of  lathe  bed,  78. 

method  of  determining  the  swing 
of  a  lathe,  77. 

tests  of  power  for  cutting  tools, 

238. 

Erecting  a  lathe,  245. 
Essential  parts  of  a  back  geared  lathe, 
58. 

of  a  triple-geared  mechanism,  131. 
Expanding  arbors,  265. 

chuck  design,  446. 

Face-plate  jaws,  261. 

jaws  for  holding  work,  269. 

work,  259. 

work,  improper  holding  of,  269. 
Factories,  early  New  England,  16. 
Failures  in  turning  tapers,  150. 
False  jaws  for  a  chuck,  262. 
Faulty  designs  of  back  gearing,  125, 

127. 
Fay    &    Scott    extension    gap    lathe, 

357. 

Fay  &  Scott's  extension,  357. 
Feeding  mechanism,  drive  for,  134. 
"Fiddle-bow"     lathe     used     by     the 

Author,  26. 
Fitchburg  machine  works  "Lo-swing" 

lathe,  350. 
Fitting  tapers,  271. 
Fixtures  for  milling,  433. 
Flat  cutters  for  boring  bars,  283. 


464 


INDEX 


Flather's  quick  change  gear  device,  212. 

18-inch  quick  change  gear  engine 

lathe,  292. 
Follow  rests,  165. 
Foot  lathes,  24. 

built  by  the  Author,  30. 

with  countershaft,  32. 
Forge  lathes,  56. 
Forming  lathe,  62. 

tools,  273. 

work,  273. 
Forms  for  pipe  centers,  264. 

of  front  bearing,  114. 

tools,  218. 

Fosdick  16-inch  engine  lathe,  325. 
Foundry,  in  Lynn,  Mass.,  1643,  17. 
Fox  brass  lathe,  56. 
Freedom,  industrial,  16. 
Friction    clutch    for    foot-power    ma- 
chines, 33. 

roller  follow  rest,  167. 
Front  bearings  for  spindles,  114. 
Full  swing  rest,  162. 
Functions  of  lathe  parts,  423. 

of  the  tail-stock,  135. 

Gap  lathe,  61. 

Gear  cutting  on  the  lathe,  284. 
Geared  countershafts,  170. 
Gearing  of  lathe  head-stocks,  120. 
Gisholt  turret  lathe,  385. 
Graduations  on  taper  attachments,  270. 
Gray's  change-gear  device,  194. 
Greenard's  arbor  press,  267. 
Grinding  attachments,  189. 

for  lathe,  450. 

large,  191. 
Grinding  operations  on  the  lathe,  284. 

tools,  220,  223,  226. 
Group  drive,  electric,  405. 
Guesswork  in  lathe  design,  132. 

Hacksaw  attachment  for  lathe,  458. 
Hamilton  compound  rest,  159. 

taper  attachment,  152. 

18-inch  engine  lathe,  320. 
Hand  lathe,  53. 

tools,  254. 
Hardened  arbors,  266. 


Head-stock,  a  favorite  form  of,  96. 

an  old  design  for,  93. 

arch  form  for,  96. 

design  of,  133. 

designing,  93. 

development  of,  95. 

favorite  form  for,  99. 

later  form  with  back  gears,  95. 

of  old  form  from  New  Haven,  95. 
Heavy  lathes,  327. 
Height  of  lathe  centers,  86. 
Hendey  cone  pulley  turning  rest,  164. 

follow  rest,  165. 

open-side  tool-post,  159. 

proportion  for  back  gearing,  133. 

quick  elevating  tool-rest,  160. 
Hendey-Norton  cabinets,  91. 

carriage,  etc.,  146. 

elevated  electric  motor  drive,  411. 

head-stock,  97. 

special  head-stock,  101. 

tail-stock,  138. 

taper  attachment,  153. 

24-inch  engine  lathe,  298. 
High-speed  drills,  227. 

lathes,  338. 

High-speed  steel  tools,  220,  223,  228, 
230. 

making  of,  228. 

use  of,  224. 

Hisey-Wolf  center  grinder,  190. 
History  of  the  lathe,  21. 
Holding  work  on  the  carriage,  274. 
Homan  patent  tool-rest,  160. 
Horn  clutches  on  countershafts,  170. 
Horse-power  transmitted  by  belts,  236. 
Horton  chucks,  260. 

Ideal  form  of  lathe  bed,  80. 

of  lathe  spindle,  104. 
Importance  of  proper  lubrication,  120. 
Indicators  and  their  use,  440. 
Industrial  freedom,  16. 
Inspection  blank,  245,  252. 
Introduction,  15. 
Inverted  V's,  368. 
Involute  bearing  for  spindle,  114. 
Iron   castings,   early  history  in   New 
England,  17. 


INDEX 


465 


Iron  Foundry  in  Lynn,  Mass.,  1643, 17. 
Irregular  lathe  work,  268. 

John  Winthrop,  his  Iron  Foundry  in 

Lynn,  17. 

Jones  &  Lamson  flat  turret  lathe,  372. 
Judd's  quick  change  gear  device,  206. 

Kinds  of  materials  to  be  turned,  216. 
Knurling  on  the  lathe,  438. 

Lantern  pinions  and  pin  wheels,  194. 
Large  grinding  attachment,  191. 
Lathe  accessories,  427. 

attachments,  176. 

attachments,  classification  of,  52. 

bed  design,  72. 

beds,  77. 

carriage,  design  of,  143. 

carriages,  84,  143. 

centers,  256. 

chucks,  259. 

classification  of,  52. 

control  methods,  425. 

design,  69. 

design  at  a  proper  medium,  70. 

dogs,  257. 

driven  by  electricity,  405. 

earliest  form  of,  23. 

foot-power,  24. 

history  of,  before  the  introduction 
of  screw  threads,  21. 

how  to  drive,  418. 

how  to  increase  swing  of,  447. 

installation  of,  418. 

its   influence    on    the   mechanical 
world,  21. 

origin  of,  22. 

origin  of  the  word,  24. 

parts  and  functions,  423. 

requisites  of  a  good,  240. 

shaft  speed  for,  420. 

speeds,  227. 

spindle,  ideal  form,  104. 

spindles,  102. 

spindles,  forms  of,  102. 

testing  of,  240. 

testing,  preparing  the  lathe,  244. 

the  fiddle-bow,  26. 


Lathe  the  first  machine  shop  tool,  22 

the  spring-pole,  24. 

tools,  157,  214. 
Lathe  work,  254. 

boring,  442. 

drilling  in,  430. 

grinding,  450. 

grooving  oil  ducts,  454. 

how  to  hold,  444. 

indicators  for,  440. 

knurling,  438. 

machining  concave  surfaces,  453. 

machining  crankshaft,  457. 

milling,  433. 

turning  a  steel  shaft,  428. 
Lathes  for  heavy  work,  449. 

lubrication  of,  422. 

power  needed  for,  421. 
Lead  screw,  apparatus  for  testing,  246. 

methods  of  driving,  135. 
Le   Blond   combination    turret    lathe, 
397. 

elevating  tool-rest,  160. 

full  swing  rest,  162. 

head-stock,  100. 

lathe  apron,  312,  315. 

lathe,  general  drawing,  313. 

lathe  head-stock,  314. 

lathes,  309. 

plain  turret  lathe,  399. 

quick  change  gear  device,  197. 

roughing  lathe,  343. 

tail-stock,  142. 

taper  attachment,  151. 

three-tool  rest,  163. 

triple-geared  turret  lathe,  391. 

24-inch  engine  lathe,  310. 
Legs  for  supporting  lathe  beds,  87. 
Lever  tail-stock,  142. 
Limits  of  variation  in  lathe  testing, 

251. 

Line-reaming  boxes,  116. 
Lipe  elevating  tool-rest,  161. 
Lodge  &  Shipley  cabinets,  90. 

compound  rest,  159. 

foUow  rest,  166. 

form  of  bed,  79. 

lathe  apron,  306. 

motor-driven  lathe)  407. 


466 


INDEX 


Lodge  &  Shipley  patent  head  lathe,  348. 

patent  lathe  head-stock,  344. 

roller  follow  rest,  166. 

tail-stock,  137. 

taper  attachment,  151. 

thrust  bearing,  111. 

triple-gear  mechanism,  132. 

20-inch  engine  lathe,  302,  304. 
Loose  chain  oiler,  119. 

ring  oiler,  118. 
"Lo-swing"  lathe,  350. 
Lubricating  lathe  centers,  257. 

the  spindle  bearings,  117. 
Lubrication    by    capillary    attraction, 
118. 

for  tools,  233. 

neglect  of,  120. 

of  lathes,  422. 

Machine  for  turning  pulley,  362. 

tools,  importance  of,  in  manufac- 
turing, 19. 

Machinery  convex  and   concave  sur- 
faces, 176. 

Machines  for  turning  pulleys,  64. 
Making  tools  of  high-speed  steel,  228. 
Mandrels  or  arbors,  265. 
Manufactures,  development  of,  20. 

view  of  the  lathe,  69. 
Manufacturing,    early   New   England, 
15. 

industries,  success  in,  15. 
"Massachusetts  Teakettle,"  18. 
Material  for  spindle  boxes,  112. 
Materials  to  be  turned,  conditions  of, 

216. 

McCabe's  double-spindle  lathe,  358. 
Mechanics,  day's  work  of  the  early,  29. 

resources  of  the  early,  17. 

tools  of  the  early  New  England,  17. 
Methods  of  holding  work,  444. 
Micrometer  stop,  187. 

straight-edge,  251. 

surface  gage,  247. 
Milling  in  the  lathe,  433. 

operations  on  the  lathe,  284. 
Modern  American  lathe  practice,  21. 
Monitor  lathe,  372. 
Motor-driven  lathes,  405. 


Multiple  spindle  lathes,  68. 
Mushet  steel  and  its  influence  on  lathe 
design,  87. 

Neglect  of  proper  oiling,  120. 
New  Haven  follow  rest,  165. 

head-stock,  100. 

lathe  carriage,  145. 

pulley  turning  lathe,  362. 

quick  change  gear  device,  206. 

shaft  straightener,  169. 

tail-stock,  138,  141. 

taper  attachment,  154. 

three-tool  shafting  rest,  163. 

thrust  bearing,  111. 

21-inch  engine  lathe,  296. 

50-inch  triple-geared  lathe,  332. 
Newton's   quick   change   gear  device, 

209. 
Niles  pulley  turning  lathe,  362. 

tail-stock,  140. 

72-inch  triple-geared  lathe,  334. 
Norton's  change  gear  device,  59,  299, 
301. 

change  gear  device  patent,  299. 
Nose  of  lathe  spindle,  105. 

Observation  and  recording  of  data,  237. 
Offset  tail-stock,  289,  294. 
Oil  cups,  plain  brass,  117. 

siphon,  117. 
Oil  ducts,  making,  454. 
Oiler,  Lodge  &  Shipley  type,  119. 

loose  chain,  119. 

loose  ring,  118. 
Oiling,  neglect  of,  120. 
Origin  of  the  lathe,  22. 

of  the  word  lathe,  24. 
Originality  in  design,  71. 

Parabolic  form  of  lathe  bed,  72,  75. 
Pattern  lathes,  53. 
Pin  wheels  and  lantern  pinions,  194. 
Pioneers  in  quick  change  gear  devices, 

299. 

Pipe  centers,  263. 

Pitman  or  connecting  rod  on  lathes,  28. 
Plain  engine  lathes,  55. 
Polishing  lathes,  53. 


INDEX 


467 


Pond  rigid  turret  lathe,  387. 

82-inch  triple-geared  lathe,  336. 
Potter's  wheel,  22. 
Power  for  driving  machines,  236,  238. 

needed  for  lathes,  421. 

required  for  cutting  tools,  238. 
Pratt  &  Whitney  chuck  mechanism,  383. 

lathe  apron,  291. 

monitor  lathe,  403. 

rod  feed  mechanism,  383. 

tail-stock,  137. 

3  x  36  turret  lathe,  380. 

14-inch  engine  lathe,  290. 
Precision  lathe,  59. 

Prentice     Bros.     Company's     16-inch 
engine  lathe,  294. 

high-speed  lathe,  338. 

motor-driven  lathes,  409. 

quick  change  gear  device,  209. 

tail-stock,  139. 

Preparing  a  lathe  for  testing,  244. 
Pressure  on  bearings  due  to  belt,  346. 
Principles  of  change-gears,  278. 
Professor  Sweet's  design   of  machine 

beds,  73. 

Progress  of  manufacturing  due  to  de- 
velopment of  machine  tools,  19. 

of  manufacturing  in  New  England, 

18. 
PuUey  lathe,  63. 

rest,  162. 

turning  lathe,  63. 

turning  machines,  64. 
Pump  for  lubricating  liquids,  235. 

Quadruple  threads,  cutting  of,  281. 
Quick   change  gear  device,  Flather's, 

212. 
change  gear  device,   Le  Blond's, 

197. 
change  gear  device,  New  Haven, 

206. 
change  gear  device,  Newton's,  209. 

Rapid  change  gear  devices,  194. 

change  gear  devices,  Bradford,  203. 
change    gear    device,    Springfield 

Machine  Tool  Co.,  200. 
reduction  lathe,  57,  60. 


Reaming  center  holes,  256. 

Rear  bearing  for  small  lathe,  113. 

Reed  compound  rest,  158. 

follow  rest,  165. 

motor-driven  lathe,  406. 

self -oiling  countershaft  boxes,  172. 

slide-rest,  157. 

spindle  boxes,  288. 

tail-stock,  137. 

Taper  attachment,  150. 

The  F.   E.   Company    and    their 
work,  287. 

turret  head  chucking  lathe,  353. 

two-tool  compound  rest,  158. 

10-inch  wood  turning  lathe,  366. 

18-inch  engine  lathe,  288. 

24-inch  special  turning  lathe,  350. 
Relieving  attachment,  185. 
Requisites  for  a  good  lathe  head,  344. 

of  a  good  lathe,  240. 
Resources  of  the  early  mechanics,  17. 
Rests,  for  early  lathes,  25. 
Retrospective  view  of  manufacturing 

development,  20. 
Revolving  tool-holder,  161. 
Rivett-Dock     thread-cutting     attach- 
ment, 192. 
Roughing  lathe,  57. 

Schumacher  &  Boye  head-stock,  99. 

tail-stock,  139,  141. 

20-inch      instantaneous      change 

gear  lathe,  307. 
Screw  machines,  67. 
Shaft  straighteners,  167. 

turning  lathe,  Springfield,  355. 
Shafting  lathes,  64. 

Self-hardening  tools,  220,  223,  228,  230. 
Set-over  mechanism  of  tail-stocks,  136. 
Setting  up  lathe,  417. 
Siphon  oil  cup,  117. 
Sizes  of  steel  for  tool-holder  tools,  220. 
Slide-rest,  157. 

South  Bend  milling  fixture,  433. 
Special  lathes,  62,  353. 

tools  for  lathe  testing,  244. 

turret  lathes,  391. 
Speeds  and  feeds,  224,  232. 

of  drills,  227. 


468 


INDEX 


Speeds  and  feeds  of  lathes,  227. 
Spindle  bearing  for  small  lathe,  113. 

bearings,  110. 

boxes,  material  for,  112. 

for  lathes,  102. 

nose  of,  105. 

proportions  for,  106. 
Spindle  speeds,  graphically  illustrated, 
125. 

with  extra  large  bearings,  107. 

with  extra  long  bearings,  107. 
Spinning  lathes,  54. 
Spring  tool,  219. 

Springfield  .engine   lathe   with   turret 
on  bed,  393. 

engine  lathe  with  turret  on  car- 
riage, 401. 

rapid  change  gear  device,  200. 

shaft  straightener,  167. 

shaft  turning  lathe,  355 

16-inch  engine  lathe,  318. 
Spring-pole  lathe,  24. 
Starting  the  lathe,  427. 
Steady  rests,  164. 
Steel,   sizes   of,  for  tool-holder  tools, 

220. 

Steps  of  a  cone,  form  of,  108. 
Stop-micrometer,  187. 
Straight-edge  for  testing  lathes,  243. 

with  micrometer  attachment,  251. 
Strength  of  tools,  217. 
Success  in  manufacturing  industries,  15. 
Successful  designing,  71. 
Summary   of  back  gear,   triple  gear, 

and  cone  conditions,  124. 
Supports  for  lathe  beds,  59. 
Surface  gage  with  micrometer  attach- 
ment, 247. 

Sweet,  Prof.  John  E.,  design  of  ma- 
chine beds,  73. 

opinions  on  lathe  beds,  76. 
Sweetland  chuck,  260. 
Swing  of  lathe,  how  to  increase,  447. 

the  English  method  of  determin- 
ing, 77. 

Tail-stocks,  135. 

features   of,    for    different    sized 
lathes,  136. 


Tail-stocks,  functions  of,  135. 

requisites  of,  136. 
Taper  arbors,  266. 

attachment  for  lathes,  432. 

attachments,  149. 

attachments,  disadvantages  of,  271. 

attachments,  graduations  on,  270. 

turning,  149. 

turning,  failures  in,  150. 

turning  lathes,  271. 
"Teakettle,"  the  Massachusetts,  18. 
Temper  of  tools,  217,  229. 
Tempering  high-speed  steel  tools,  229. 
Test  pieces  for  use  in  lathe  testing,  251. 
Testing  a  lathe,  240. 

a  lathe  for  true  boring,  250. 

a  lead  screw,  246. 

alignment  of  head-stock  and  tail- 
stock  spindles,  249. 

bar  for  lathe  testing,  242. 

for  alignment  of  tail  spindle,  243. 

for  parallelism,  250. 

micrometer  for  lathe  testing,  242. 
Thread-cutting  attachment,  the  Rivett- 
Dock,  192. 

cutting,  and  the  use  of  change- 
gears,  277. 

cutting  devices,  59. 

cutting  on  a  modern  lathe,  277. 
Three-in-one  tool-holder,  222. 
Three-tool  shafting  rest,  163,  355. 

turning  rest,  163. 
Thrust  bearings  for  spindle,  110. 
Tool  angles,  216,  218. 
Tools,  clearance  of,  218. 

design  of,  217. 

for  the  lathe,  214. 

for  tool-holders,  220. 

form  of,  218. 

holder  tools,  220. 

holder  tools,  sizes  of  steel  for,  220. 

holders,  221. 

lubrication  of,  233. 

of  the  early   New  England   me- 
chanic, 17. 

post  grinding  attachment,  189. 

rests,  158. 

set  of,  for  lathe,  215. 

strength  of,  217. 


INDEX 


469 


Tools,  temper  of,  217,  229. 
Track,  for  beds,  83. 
Treadle,  as  used  on  foot  lathes,  28. 
"Tree  lathe,"  23. 

Triple  gear  mechanism,  essential  parts, 
131. 

gear  speeds,  129. 

geared  lathe,  57. 

gearing  of  head-stocks,  121. 

threads,  cutting  of,  281. 
Turning  balls,  179. 

convex  and  concave  rolls,  181. 

crank-shafts,  271. 

definitions  of,  22. 

tapers,  269. 
Turret  head  chucking  lathe,  55. 

lathe,  importance  of,  370. 

lathes,  65,  370. 

lathes,  classification  of,  371. 
Two-speed  countershafts,  170. 

Use  of  arbors,  267. 


Use  of  change-gears  in  thread  cutting, 

278. 

of  high-speed  steel  tools,  224. 
of  indicators,  440. 
of  lubricant  for  tools,  234. 

V's,  for  lathe  beds,  84. 
Variable  speed  countershaft,  173. 

Waltham  bench  lathe,  364. 

Warner    &    Swasey    complete    turret 

lathe,  377. 

Universal  turret  lathe,  376. 
Watchmakers'  early  lathes,  27. 
Water   power   mostly   used   by   early 

mechanics,  18. 
Wing  rest,  162. 
Wood  turning  in  Asia,  24. 

turning  lathe,  Reed  10-inch,  366. 
Wooden  beds,  86. 
Work,  amount  of,  on  machine  tools, 

226. 


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